At most, someone who intentionally or repeatedly shares information on their social platform that’s misleading or downright false may have their account blocked, suspended or deleted.

Thursday, April 18, 2024 14:00

If you’re a regular reader of this newsletter, you already know about how strongly I feel about the dangers of spreading fake news, disinformation and misinformation. 

And honestly, if you’re reading this newsletter, I probably shouldn’t have to tell you about that either. But one of the things that always frustrates me about this seemingly never-ending battle against disinformation on the internet, is that there aren’t any real consequences for the worst offenders. 

At most, someone who intentionally or repeatedly shares information on their social platform that’s misleading or downright false may have their account blocked, suspended or deleted, or just that one individual post might be removed.  

Twitter, which has become one of the worst offenders for spreading disinformation, has gotten even worse about this over the past few years and at this point doesn’t do anything to these accounts, and in fact, even promotes them in many ways and gives them a larger platform. 

Meta, for its part, is now hiding more political posts on its platforms in some countries, but at most, an account that shares fake news is only going to be restricted if enough people report it to Meta’s team and they choose to take action.  

Now, I’m hoping that Brazil’s Supreme Court may start imposing some real-world consequences on individuals and companies that support, endorse or sit idly by while disinformation spreads. Specifically, I’m talking about a newly launched investigation by the court into Twitter/X and its owner, Elon Musk.  

Brazil’s Supreme Court says users on the platform are part of a massive misinformation campaign against the court’s justices, sharing intentionally false or harmful information about them. Musk is also facing a related investigation into alleged obstruction.  

The court had previously asked Twitter to block certain far-right accounts that were spreading fake news on Twitter, seemingly one of the only true permanent bans on a social media platform targeting the worst misinformation offenders. Recently, Twitter has declined to block those accounts. 

This isn’t some new initiative, though. Brazil’s government has long looked for concrete ways to implement real-world punishments for spreading disinformation. In 2022, the Supreme Court signed an agreement with the equivalent of Brazil’s national election commission “to combat fake news involving the judiciary and to disseminate information about the 2022 general elections.” 

Brazil’s president (much like the U.S.) has been battling fake news and disinformation for years now, making any political conversation there incredibly divisive, and in many ways, physically dangerous. I’m certainly not an authority enough on the subject to comment on that and the ways in which the term “fake news” has been weaponized to literally challenge what is “fact” in our modern society.  

And I could certainly see a world in which a high court uses the term “fake news” to charge and prosecute people who are, in fact, spreading \*correct\* and verifiable information.  

But, even just forcing Musk or anyone at Twitter to answer questions about their blocking policies could bring an additional layer of transparency to this process. Suppose we want to really get people to stop sharing misleading information on social media. In that case, it needs to eventually come with real consequences, not just a simple block when they can launch a new account two seconds later using a different email address. 

**The one big thing **

Talos recently discovered a new threat actor we're calling “Starry Addax” targeting mostly human rights activists associated with the Sahrawi Arab Democratic Republic (SADR) cause. Starry Addax primarily uses a new mobile malware that it infects users with via phishing attack, tricking their targets into installing malicious Android applications we’re calling “FlexStarling.” The malicious mobile application (APK), “FlexStarling,” analyzed by Talos recently masquerades as a variant of the Sahara Press Service (SPSRASD) App. 

**Why do I care? **

The targets in this campaign's case are considered high-risk individuals, advocating for human rights in the Western Sahara. While that is a highly focused particular demographic, FlexStarling is still a highly capable implant that could be dangerous if used in other campaigns. Once infected, Starry Addax can use their malware to steal important login credentials, execute remote code or infect the device with other malware.  

**So now what? **

This campaign's infection chain begins with a spear-phishing email sent to targets, consisting of individuals of interest to the attackers, especially human rights activists in Morocco and the Western Sahara region. If you are a user who feels you could be targeted by these emails, please pay close attention to any URLs or attachments used in emails with these themes and ensure you’re only visiting trusted sites. The timelines connected to various artifacts used in the attacks indicate that this campaign is just starting and may be in its nascent stages with more infrastructure and Starry Addax working on additional malware variants. 

**Top security headlines of the week **

**A threat actor with ties to Russia is suspected of infecting the network belonging to a rural water facility in Texas earlier this year.** The hack in the small town of Muleshoe, Texas in January caused a water tower to overflow. The suspect attack coincided with network intrusions against networks belonging to two other nearby towns. While the attack did not disrupt drinking water in the town, it would mark an escalation in Russian APTs’ efforts to spy on and disrupt American critical infrastructure. Security researchers this week linked a Telegram channel that took credit for the activity with a group connected to Russia’s GRU military intelligence agency. The adversaries broke into a remote login system used in ICS, which allowed the actors to interact with the water tank. It overflowed for about 30 to 45 minutes before officials took the machine offline and switched to manual operations. According to reporting from CNN, a nearby town called Lockney detected “suspicious activity” on the town’s SCADA system. And in Hale Center, adversaries also tried to breach the town network’s firewall, which prompted them to disable remote access to its SCADA system. (CNN, Wired) 

**Meanwhile, Russia’s Sandworm APT is also accused of being the primary threat actor carrying out Russia’s goals in Ukraine.** New research indicates that the group is responsible for nearly all disruptive and destructive cyberattacks in Ukraine since Russia's invasion in February 2022. One attack involved Sandworm, aka APT44, disrupting a Ukrainian power facility during Russia’s winter offensive and a series of drone strikes targeting Ukraine’s energy grid. Recently, the group’s attacks have increasingly focused on espionage activity to gather information for Russia’s military to use to its advantage on the battlefield. The U.S. indicated several individuals for their roles with Sandworm in 2020, but the group has been active for more than 10 years. Researchers also unmasked a Telegram channel the group appears to be using, called “CyberArmyofRussia\_Reborn.” They typically use the channel to post evidence from their sabotage activities. (Dark Reading, Recorded Future) 

**Security experts and government officials are bracing for an uptick in offensive cyber attacks between Israel and Iran** after Iran launched a barrage of drones and missiles at Israel. Both countries have dealt with increased tensions recently, eventually leading to the attack Saturday night. Israel’s leaders have already been considering various responses to the attack, among which could be cyber attacks targeting Iran in addition to any new kinetic warfare. Israel and Iran have long had a tense relationship that included covert operations and destructive cyberattacks. Experts say both countries have the ability to launch wiper malware, ransomware and cyber attacks against each other, some of which could interrupt critical infrastructure or military operations. The increased tensions have also opened the door to many threat actors taking claims for various cyber attacks or intrusions that didn’t happen. (Axios, Foreign Policy) 

**Can’t get enough Talos? **

*   Cisco Warns of Global Surge in Brute-Force Attacks Targeting VPN and SSH Services 
*   Decade-old malware haunts Ukrainian police 
*   Attackers are pummeling networks around the world with millions of login attempts 
*   OfflRouter virus causes Ukrainian users to upload confidential documents to VirusTotal 
*   Large-scale brute-force activity targeting VPNs, SSH services with commonly used login credentials 
*   Talos Takes Ep. #179: Why we need to stop calling as-a-service group takedowns "takedowns" 

**Upcoming events where you can find Talos **

 **Botconf** **(April 23 - 26)** 

_Nice, Côte d'Azur, France_

> _This presentation from Chetan Raghuprasad details the Supershell C2 framework. Threat actors are using this framework massively and creating botnets with the Supershell implants._

**CARO Workshop 2024** **(May 1 - 3)** 

_Arlington, Virginia_

> Over the past year, we’ve observed a substantial uptick in attacks by YoroTrooper, a relatively nascent espionage-oriented threat actor operating against the Commonwealth of Independent Countries (CIS) since at least 2022. Asheer Malhotra's presentation at CARO 2024 will provide an overview of their various campaigns detailing the commodity and custom-built malware employed by the actor, their discovery and evolution in tactics. He will present a timeline of successful intrusions carried out by YoroTrooper targeting high-value individuals associated with CIS government agencies over the last two years.

**RSA** **(May 6 - 9)** 

_San Francisco, California_    

**Most prevalent malware files from Talos telemetry over the past week **

_This section will be on a brief hiatus while we work through some technical difficulties._

Could the Brazilian Supreme Court finally hold people accountable for sharing disinformation?

The documents contained malicious VBA code, indicating they may be used as lures to infect organizations.

*   During a threat-hunting exercise, Cisco Talos discovered documents with potentially confidential information originating from Ukraine. The documents contained malicious VBA code, indicating they may be used as lures to infect organizations. 
*   The results of the investigation have shown that the presence of the malicious code is due to the activity of a rare multi-module virus that's delivered via the .NET interop functionality to infect Word documents. 
*   The virus, named OfflRouter, has been active in Ukraine since 2015 and remains active on some Ukrainian organizations’ networks, based on over 100 original infected documents uploaded to VirusTotal from Ukraine and the documents’ upload dates. 
*   We assess that OfflRouter is the work of an inventive but relatively inexperienced developer, based on the unusual choice of the infection mechanism, the apparent lack of testing and mistakes in the code. 
*   The author’s design choices may have limited the spread of the virus to very few organizations while allowing it to remain active and undetected for a long period of time. 

As a part of a regular threat hunting exercise, Cisco Talos monitors files uploaded to open-source repositories for potential lures that may target government and military organizations. Lures are created from legitimate documents by adding content that will trigger malicious behavior and are often used by threat actors. 

For example, malicious document lures with externally referenced templates written in Ukrainian language are used by the Gamaredon group as an initial infection vector. Talos has previously discovered military theme lures in Ukrainian and Polish, mimicking the official PowerPoint and Excel files, to launch the so-called “Picasso loader,” which installs remote access trojans (RATs) onto victims' systems. 

In July 2023, threat actors attempted to use lures related to the NATO summit in Vilnius to install the Romcom remote access trojan. These are just some of the reasons why hunting for document lures is vital to any threat intelligence operation.  

In February 2024, Talos discovered several documents with content that seems to originate from Ukrainian local government organizations and the Ukrainian National Police uploaded to VirusTotal. The documents contained VBA code to drop and run an executable with the name \`ctrlpanel.exe\`, which raised our suspicion and prompted us to investigate further.   

Eventually, we discovered over 100 uploaded documents with potentially confidential information about government and police activities in Ukraine. The analysis of the code showed unexpected results – instead of lures used by advanced actors, the uploaded documents were infected with a multi-component VBA macro virus OfflRouter, created in 2015. The virus is still active in Ukraine and is causing potentially confidential documents to be uploaded to publicly accessible document repositories.   

**Attribution **

Although the virus is active in Ukraine, there are no indications that it was created by an author from that region. Even the debugging database string used to name the virus “E:\\Projects\\OfflRouter2\\OfflRouter2\\obj\\Release\\ctrlpanel.pdb” present in the ctrlpanel.exe does not point to a non-English speaker. 

From the choice of the infection mechanism, VBA code generation, several mistakes in the code, and the apparent lack of testing, we estimate that the author is an inexperienced but inventive programmer.  

The choices made during the development limited the virus to a specific geographic location and allowed it to remain active for almost 10 years. 

**OfflRouter has been confined to Ukraine **

According to earlier research by the Slovakian government CSIRT (Computer Security Incident Response Team) team, some infected documents were already publicly available on the Ukrainian National Police website in 2018.  

The newly discovered infected documents are written in Ukrainian, which may have contributed to the fact that the virus is rarely seen outside Ukraine. Since the malware has no capabilities to spread by email, it can only be spread by sharing documents and removable media, such as USB memory sticks with infected documents. The inability to spread by email and the initial documents in Ukrainian are additional likely reasons the virus stayed confined to Ukraine.  

One of the documents was recently uploaded to VirusTotal from Ukraine. 

The virus targets only documents with the filename extension .doc, the default extension for the OLE2 documents, and it will not try to infect other filename extensions. The default Word document filename extension for the more recent Word versions is .docx, so few documents will be infected as a result.  

This is a possible mistake by the author, although there is a small probability that the malware was specifically created to target a few organizations in Ukraine that still use the .doc extension, even if the documents are internally structured as Office Open XML documents.  

Other issues prevented the virus from spreading more successfully and most of them are found in the executable module, ctrlpanel.exe, dropped and executed by the VBA part of the code.  

When the virus is run, it attempts to set the value Ctrlpanel of the registry key HKLM\\Software\\Microsoft\\Windows\\CurrentVersion\\Run so that it runs on the Windows boot. An internal global string \_RootDir is used as the value, however, the string only contains the folder where the ctrlpanel.exe is found and not its full path, which makes this auto-start measure fail.  

One interesting concept in the .NET module is the entire process of infecting documents. As a part of the infection process, the VBA code is generated by combining the code taken from the hard-coded strings in the module with the encoded bytes of the ctrlpanel.exe binary. This makes the generated code the same for every infection cycle and rather easy to detect. Having a VBA code generator in the .NET code has more potential to make the infected documents more difficult to detect.  

Once launched, the executable module stays active in memory and uses threading timers to execute two background worker objects, the first one tasked with the infection of documents and the second one with checking for the existence of the potential plugin modules for the .NET module.  

The infection background worker enumerates the mounted drives and attempts to find documents to infect by using the Directory.Getfiles function with the string search pattern “\*.doc” as a parameter.  

One of the parameters of the function is the SearchOption parameter which specifies the option to search in subdirectories or only the in the root folder. For fixed drives, the module chooses to search only the root folder, which is an unusual choice, as it is quite unlikely that the root folder will hold any documents to infect.  

For removable drives, the module also searches all subfolders, which likely makes it more successful. Finally, it checks the list of recent documents in Word and attempts to infect them, which contributes to the success of the virus spreading to other documents on fixed drives.  

__The choice of document filename extensions is limited to .doc.__

**OfflRouter VBA code drops and executes the main executable module **

The VBA part of the virus runs when a document is opened, provided macros are enabled, and it contains code to drop and run the executable module ctrlpanel.exe.

__The VBA part creates and executes the executable module of the virus.__

 The beginning of the macro code defines a function that checks if the file already exists and if it does not, it opens it for writing and calls functions CheckHashX, which at first glance looks like containing junk code to reset the value of the variable \`Y\`. However, the variable Y is defined as a private property with an overridden setter function, which converts the variable value assignment into appending the supplied value to the end of the opened executable module C:\\Users\\Public\\ctrlpanel.exe. Every code line that looks like an assignment appends the assigned value to the end of the file, and that is how the executable module is written.  

This technique is likely implemented to make the detection of the embedded module a bit more difficult, as the executable mode is not stored as a contiguous block, but as a sequence of integer values that look like being assigned to a variable.  

To a more experienced analyst, this code looks like garbage code generated by polymorphic engines, and it raises the question of why the author has not extended the code generation to pseudo-randomize the code.  

__Infected Word documents drop the .NET component that infects other documents__. 

The virus is unique, as it consists of VBA and executable modules with the infection logic contained in the PE executable .NET module.  

__The property Y has an overridden setter function to write into a file.__

**Ctrlpanel.exe .NET module **

The unique infection method used by ctrlpanel.exe is through the Office Interop classes of .NET VBProject interface Microsoft.Vbe.Interop and the Microsoft.Office.Interop.Word class that exposes the functionality of the Word application.  

The Interop.Word class is used to instantiate a Document class which allows access to the VBA macro code and the addition of the code to the target document file using the standard Word VBA functions.  

When the .NET module ctrlpanel.exe is launched, it attempts to open a mutex ctrlpanelapppppp to check if another module instance is already running on the system. If the mutex already exists, the process will terminate.  

Suppose no other module instances are running. In that case, ctrlpanel.exe creates the mutex named “ctrlpanelapppppp”, attempts to set the registry run key so the module runs on system startup, and finally initializes two timers to run associated background timer callbacks – VBAClass\_Timer\_Callback and PluginClass\_TimerCallback, implemented to start the Run function of the classes VBAClass and PluginClass, respectively. 

__Ctrlpanel.exe has two threads of execution.__

The VBAClass\_Timer\_Callback will be called one second after the creation of VBAClass\_Timer timer and the PluginClass\_Timer\_Callback three seconds after the creation of the PluginClass\_Timer.  

The full functionality of the executable module is implemented by two classes, VBAClass and PluginClass, specifically within their respective functions Backgroundworker\_DoWork. 

**_VBAClass is tasked with generating VBA code and infecting other Word documents_ **

 The background worker function runs in an infinite loop and contains two major parts, the first is tasked with the document infection and the second with finding the documents to infect, the logic we already described above.  

The infection iterates through a list of the document candidates to infect and uses an innovative method to check the document infection marker to avoid multiple infection processes – the function checks the document creation metadata, adds the creation times, and checks the value of the sum. If the sum is zero, the document is considered already infected.  

__The file system time of creation is used as an infection marker.__

If the document to be infected is created in the Word 97-2003 binary format (OLE2), the document will be saved with the same name in Microsoft Office Open XML format with enabled macros (DOCX).  

The infection uses the traditional VBA class infection routine. It accesses the Visual Basic code module of the first VBComponent and then adds the code generated by the function MyScript to the document’s code module. After that, the infected document is saved.  

__The target document is converted to .docx and then infected.__

The code generation function MyScript contains static strings and instructions to dynamically generate code that will be added to infected documents. It opens its own executable ctrlpanel.exe for reading and reads the file 32-bit by 32-bit value which gets converted to decimal strings that can be saved as VBA code. For every repeating 32-bit value, most commonly for zero, the function creates a for loop to write the repeating value to the dropped file. The purpose is unclear, but it is likely to achieve a small saving in the size of the code and compress it.  

__Repeating 32-bit values are “compressed.”__

For every 4,096 bytes, the code generates a new CheckHashX subroutine to break the code into chunks. The purpose of this is not clear.  

__The VBA code infecting files is dynamically created.__

 After the file is infected, the background worker adds the infection marker file by setting the values of hour, minute, second, and millisecond creation times to zero.

__The infection market is set after the infected file has been copied to its original location.__

**_PluginClass is tasked with discovering and loading plugins_ **

Ctrlpanel.exe can also search for potential plugins present on removable media, which is very unusual for simple viruses that infect documents. This may indicate that the author’s aims were a bit more ambitious than the simple VBA infection. 

Searching for the plugins in removable drives is unusual as it requires the plugins to be delivered to the system on a physical media, such as a USB drive or a CD-ROM. The plugin loader searches for any files with the filename extension .orp, decodes its name using Base64 decoding function, decodes the file content using Base64 decoding, copies the file into the c:\\users\\public\\tools folder with the previously decoded name and the extension .exe and finally executes the plugin. 

__Any plugins found on a removable drive are decoded, copied to drive C: and launched.__

If the plugins are already present on an infected machine, ctrlpanel.exe will try to encode them using Base64 encoding, copy them to the root of the attached removable media with the filename extension “.orp” and set the newly created file attributes to the values system and hidden so that they are not displayed by default by Windows File Explorer. 

**It is unclear if the initial vector is a document or the executable module ctrlpanel.exe **

The advantage of the two-module virus is that it can be spread as a standalone executable or as an infected document. It may even be advantageous to initially spread as an executable as the module can run standalone and set the registry keys to allow execution of the VBA code and changing of the default saved file formats to doc before infecting documents. That way, the infection may be a bit stealthier.  

The following registry keys are set: 
HKEY\_CURRENT\_USER\\Software\\Microsoft\\Office\\14.0\\Word\\Security\\AccessVBOM (to allow access to Visual Basic Object Model by the external applications) 
  
HKEY\_CURRENT\_USER\\Software\\Microsoft\\Office\\14.0\\Word\\Security\\VBAWarnings (to disable warnings about potential Macro code in the infected documents) 
  
HKEY\_CURRENT\_USER\\Software\\Microsoft\\Office\\14.0\\Word\\Options\\DefaultFormat (to set the default format to DOC) 

**Coverage **

Ways our customers can detect and block this threat are listed below. 

Cisco Secure Endpoint (formerly AMP for Endpoints) is ideally suited to prevent the execution of the malware detailed in this post. Try Secure Endpoint for free here.  

Cisco Secure Email (formerly Cisco Email Security) can block malicious emails sent by threat actors as part of their campaign. You can try Secure Email for free here. 

Cisco Secure Firewall (formerly Next-Generation Firewall and Firepower NGFW) appliances such as Threat Defense Virtual, Adaptive Security Appliance and Meraki MX can detect malicious activity associated with this threat. 

Cisco Secure Network/Cloud Analytics (Stealthwatch/Stealthwatch Cloud) analyzes network traffic automatically and alerts users of potentially unwanted activity on every connected device.  

Cisco Secure Malware Analytics (formerly Threat Grid) identifies malicious binaries and builds protection into all Cisco Secure products. 

Umbrella, Cisco’s secure internet gateway (SIG), blocks users from connecting to malicious domains, IPs and URLs, whether users are on or off the corporate network. Sign up for a free trial of Umbrella here. 

Cisco Secure Web Appliance (formerly Web Security Appliance) automatically blocks potentially dangerous sites and tests suspicious sites before users access them.  

Additional protection with context to your specific environment and threat data are available from the Firewall Management Center.  

Cisco Duo provides multi-factor authentication for users to ensure only those authorized are accessing your network.  

Open-source Snort Subscriber Rule Set customers can stay up to date by downloading the latest rule pack available for purchase on Snort.org. Snort SIDs for this threat are  

The following ClamAV signatures detect malware artifacts related to this threat: 

Doc.Malware.Valyria-6714124-0 

Win.Virus.OfflRouter-10025942-0 

**IOCs **

IOCs for this research can also be found at our GitHub repository here. 

10e720fbcf797a2f40fbaa214b3402df14b7637404e5e91d7651bd13d28a69d8 - .NET module ctrlpanel.exe  

**Infected documents  **

2260989b5b723b0ccd1293e1ffcc7c0173c171963dfc03e9f6cd2649da8d0d2c 

2b0927de637d11d957610dd9a60d11d46eaa3f15770fb474067fb86d93a41912 

802342de0448d5c3b3aa6256e1650240ea53c77f8f762968c1abd8c967f9efd0 

016d90f337bd55dfcfbba8465a50e2261f0369cd448b4f020215f952a2a06bce 

**Mutex **

ctrlpanelapppppp

OfflRouter virus causes Ukrainian users to upload confidential documents to VirusTotal

Cisco Talos would like to acknowledge Brandon White of Cisco Talos and Phillip Schafer, Mike Moran, and Becca Lynch of the Duo Security Research team for their research that led to the ,identification of these attacks.
Cisco Talos is actively monitoring a global increase in brute-force attacks against a variety

Tuesday, April 16, 2024 08:00

_Cisco Talos would like to acknowledge Brandon White of Cisco Talos and Phillip Schafer, Mike Moran, and Becca Lynch of the Duo Security Research team for their research that led to the_ ,_identification of these attacks._

Cisco Talos is actively monitoring a global increase in brute-force attacks against a variety of targets, including Virtual Private Network (VPN) services, web application authentication interfaces and SSH services since at least March 18, 2024.  

These attacks all appear to be originating from TOR exit nodes and a range of other anonymizing tunnels and proxies.  

Depending on the target environment, successful attacks of this type may lead to unauthorized network access, account lockouts, or denial-of-service conditions. The traffic related to these attacks has increased with time and is likely to continue to rise. Known affected services are listed below. However, additional services may be impacted by these attacks. 

*   Cisco Secure Firewall VPN 
*   Checkpoint VPN  
*   Fortinet VPN  
*   SonicWall VPN  
*   RD Web Services 
*   Miktrotik 
*   Draytek 
*   Ubiquiti 

The brute-forcing attempts use generic usernames and valid usernames for specific organizations. The targeting of these attacks appears to be indiscriminate and not directed at a particular region or industry. The source IP addresses for this traffic are commonly associated with proxy services, which include, but are not limited to:  

*   TOR   
*   VPN Gate  
*   IPIDEA Proxy  
*   BigMama Proxy  
*   Space Proxies  
*   Nexus Proxy  
*   Proxy Rack 

The list provided above is non-exhaustive, as additional services may be utilized by threat actors.  

Due to the significant increase and high volume of traffic, we have added the known associated IP addresses to our blocklist. It is important to note that the source IP addresses for this traffic are likely to change.

**Guidance **

As these attacks target a variety of VPN services, mitigations will vary depending on the affected service. For Cisco remote access VPN services, guidance and recommendation can be found in a recent Cisco support blog:  

Best Practices Against Password Spray Attacks Impacting Remote Access VPN Services 

**IOCs **

We are including the usernames and passwords used in these attacks in the IOCs for awareness. IP addresses and credentials associated with these attacks can be found in our GitHub repository here.

Large-scale brute-force activity targeting VPNs, SSH services with commonly used login credentials

The security community is still reflecting on the “What If” of the XZ backdoor.

Thursday, April 11, 2024 14:00

I feel like over the past several years, the “holiday” that is April Fool’s Day has really died down. At this point, there are few headlines you can write that would be more ridiculous than something you’d find on a news site any day of the week. 

And there are so many more serious issues that are developing, too, that making a joke about a fake news story is just in bad taste, even if it’s in “celebration” of a “holiday.” 

Thankfully in the security world, I think we’ve all gotten the hint at this point that we can’t just post whatever we want on April 1 of each calendar year and expect people to get the joke. I’ve put my guard down so much at this point that I actually did legitimately fall for one April Fool’s joke from Nintendo, because I could definitely see a world in which they release a Virtual Boy box for the Switch that would allow you to play virtual reality games. 

But at least from what I saw on April 1 of this year, no one tried to “get” anyone with an April Fool’s joke about a ransomware actor requesting payment in the form of “Fortnite” in-game currency, or an internet-connected household object that in no universe needs to be connected to the internet (which, as it turns out, smart pillows exist!).  

We’re already dealing with digitally manipulated photos of “Satanic McDonalds,” Twitter’s AI generating fake news about the solar eclipse, and an upcoming presidential election that is sure to generate a slew of misinformation, AI-generated photos and more that I hesitate to even make up. 

So, all that is to say, good on you, security community, for just letting go of April Fool’s. Our lives are too stressful without bogus headlines that we, ourselves, generate.  

**The one big thing **

Talos discovered a new threat actor we’re calling “CoralRaider” that we believe is of Vietnamese origin and financially motivated. CoralRaider has been operating since at least 2023, targeting victims in several Asian and Southeast Asian countries. This group focuses on stealing victims’ credentials, financial data, and social media accounts, including business and advertisement accounts. CoralRaider appears to use RotBot, a customized variant of QuasarRAT, and XClient stealer as payloads. The actor uses the dead drop technique, abusing a legitimate service to host the C2 configuration file and uncommon living-off-the-land binaries (LoLBins), including Windows Forfiles.exe and FoDHelper.exe 

**Why do I care? **

This is a brand new actor that we believe is acting out of Vietnam, traditionally not a country who is associated with high-profile state-sponsored actors. CoralRaider appears to be after targets’ social media logins, which can later be leveraged to spread scams, misinformation, or all sorts of malicious messages using the victimized account. 

**So now what? **

CoralRaider primarily uses malicious LNK files to spread their malware, though we currently don’t know how those files are spread, exactly. Threat actors have started shifting toward using LNK files as an initial infection vector after Microsoft disabled macros by default — macros used to be a primary delivery system. For more on how the info in malicious LNK files can allow defenders to learn more about infection chains, read our previous research here. 

**Top security headlines of the week **

**The security community is still reflecting on the “What If” of the XZ backdoor** that was discovered and patched before threat actors could exploit it. A single Microsoft developer, who works on a different open-source project, found the backdoor in xz Utils for Linux distributions several weeks ago seemingly on accident, and is now being hailed as a hero by security researchers and professionals. Little is known about the user who had been building the backdoor in the open-source utility for at least two years. Had it been exploited, the vulnerability would have allowed its creator to hijack a user’s SSH connection and secretly run their own code on that user’s machine. The incident is highlighting networking’s reliance on open-source projects, which are often provided little resource and usually only maintained as a hobby, for free, by individuals who have no connection to the end users. The original creator of xz Utils worked alone for many years, before they had to open the project because of outside stressors and other work. Government officials have also been alarmed by the near-miss, and are now considering new ways to protect open-source software. (New York Times, Reuters) 

**AT&T now says that more than 51 million users were affected by a data breach** that exposed their personal information on a hacking forum. The cable, internet and cell service provider has still not said how the information was stolen. The incident dates back to 2021, when threat actor ShinyHunters initially offered the data for sale for $1 million. However, that data leaked last month on a hacking forum belonging to an actor known as “MajorNelson.” AT&T’s notification to affected customers stated that, "The \[exposed\] information varied by individual and account, but may have included full name, email address, mailing address, phone number, social security number, date of birth, AT&T account number and AT&T passcode." The company has also started filing required formal notifications with U.S. state authorities and regulators. While AT&T initially denied that the data belonged to them, reporters and researchers soon found that the information were related to AT&T and DirecTV (a subsidiary of AT&T) accounts. (BleepingComputer, TechCrunch) 

**Another ransomware group claims they’ve stolen data from United HealthCare, though there is little evidence yet to prove their claim.** Change Health, a subsidiary of United, was recently hit with a massive data breach, pausing millions of dollars of payments to doctors and healthcare facilities to be paused for more than a month. Now, the ransomware gang RansomHub claims it has 4TB of data, requesting an extortion payment from United, or it says it will start selling the data to the highest bidder 12 days from Monday. RansomHub claims the stolen information contains the sensitive data of U.S. military personnel and patients, as well as medical records and financial information. Blackcat initially stated they had stolen the data, but the group quickly deleted the post from their leak site. A person representing RansomHub told Reuters that a disgruntled affiliate of Blackcat gave the data to RansomHub after a previous planned payment fell through. (DarkReading, Reuters) 

**Can’t get enough Talos? **

*   Talos Takes Ep. #178: Turla has been around for 20-plus years at this point, but they're still mixing things up 
*   Vulnerability in some TP-Link routers could lead to factory reset 
*   April’s Patch Tuesday includes 150 vulnerabilities, 60 which could lead to remote code execution 
*   Vietnamese Cybercrime Group CoralRaider Nets Financial Data 
*   Safeguarding Against CoralRaider: Protecting Your Data from Vietnamese Hackers 

**Upcoming events where you can find Talos **

**Botconf** **(April 23 - 26)** 

_Nice, Côte d'Azur, France_

> _This presentation from Chetan Raghuprasad details the Supershell C2 framework. Threat actors are using this framework massively and creating botnets with the Supershell implants._

**CARO Workshop 2024** **(May 1 - 3)** 

_Arlington, Virginia_

> Over the past year, we’ve observed a substantial uptick in attacks by YoroTrooper, a relatively nascent espionage-oriented threat actor operating against the Commonwealth of Independent Countries (CIS) since at least 2022. Asheer Malhotra's presentation at CARO 2024 will provide an overview of their various campaigns detailing the commodity and custom-built malware employed by the actor, their discovery and evolution in tactics. He will present a timeline of successful intrusions carried out by YoroTrooper targeting high-value individuals associated with CIS government agencies over the last two years.

**RSA** **(May 6 - 9)** 

_San Francisco, California_    

**Most prevalent malware files from Talos telemetry over the past week **

**SHA 256:** c67b03c0a91eaefffd2f2c79b5c26a2648b8d3c19a22cadf35453455ff08ead0  
**MD5:** 8c69830a50fb85d8a794fa46643493b2  
**Typical Filename:** AAct.exe  
**Claimed Product:** N/A  
**Detection Name:** PUA.Win.Dropper.Generic::1201

**SHA 256:** abaa1b89dca9655410f61d64de25990972db95d28738fc93bb7a8a69b347a6a6  
**MD5:** 22ae85259273bc4ea419584293eda886  
**Typical Filename:** KMSAuto++ x64.exe  
**Claimed Product:** KMSAuto++  
**Detection Name:** W32.File.MalParent

**SHA 256:** 161937ed1502c491748d055287898dd37af96405aeff48c2500b834f6739e72d  
**MD5:** fd743b55d530e0468805de0e83758fe9  
**Typical Filename:** KMSAuto Net.exe  
**Claimed Product:** KMSAuto Net  
**Detection Name:** PUA.Win.Tool.Kmsauto::1201

**SHA 256:** b8aec57f7e9c193fcd9796cf22997605624b8b5f9bf5f0c6190e1090d426ee31  
**MD5:** 2fb86be791b4bb4389e55df0fec04eb7  
**Typical Filename:** KMSAuto Net.exe  
**Claimed Product:** KMSAuto Net  
**Detection Name:** W32.File.MalParent

**SHA 256:** 58d6fec4ba24c32d38c9a0c7c39df3cb0e91f500b323e841121d703c7b718681  
**MD5:** f1fe671bcefd4630e5ed8b87c9283534  
**Typical Filename:** KMSAuto Net.exe  
**Claimed Product:** KMSAuto Net  
**Detection Name:** PUA.Win.Tool.Hackkms::1201

The internet is already scary enough without April Fool’s jokes

There are also two out-of-bounds write vulnerabilities in the AMD Radeon user mode driver for DirectX 11.

Wednesday, April 10, 2024 12:56

Cisco Talos’ Vulnerability Research team has disclosed 10 vulnerabilities over the past three weeks, including four in a line of TP-Link routers, one of which could allow an attacker to reset the devices’ settings back to the factory default. 

A popular open-source software for internet-of-things (IoT) and industrial control systems (ICS) networks also contains multiple vulnerabilities that could be used to arbitrarily create new files on the affected systems or overwrite existing ones. 

For Snort coverage that can detect the exploitation of these vulnerabilities, download the latest rule sets from Snort.org, and our latest Vulnerability Advisories are always posted on Talos Intelligence’s website.  

**Denial-of-service, remote code execution vulnerabilities in TP-Link AC1350 router **

Talos researchers recently discovered four vulnerabilities in the TP-Link AC1350 wireless router. The AC1350 is one of many routers TP-Link produces and is designed to be used on home networks. 

TALOS-2023-1861 (CVE-2023-49074) is a denial-of-service vulnerability in the TP-Link Device Debug Protocol (TDDP). An attacker could exploit this vulnerability by sending a series of unauthenticated packets to the router, potentially causing a denial of service and forcing the device to reset to its factory settings.  

However, the TDDP protocol is only denial of serviceavailable for roughly 15 minutes after a device reboot.  

The TDDP protocol is also vulnerable to TALOS-2023-1862 (CVE-2023-49134 and CVE-2023-49133), a command execution vulnerability that could allow an attacker to execute arbitrary code on the targeted device. 

There is another remote code execution vulnerability, TALOS-2023-1888 (CVE-2023-49912, CVE-2023-49909, CVE-2023-49907, CVE-2023-49908, CVE-2023-49910, CVE-2023-49906, CVE-2023-49913, CVE-2023-49911) that is triggered if an attacker sends an authenticated HTTP request to the targeted device. This exploit includes multiple CVEs because an attacker could overflow multiple buffers to cause this condition. 

TALOS-2023-1864 (CVE-2023-48724) also exists in the device’s web interface functionality. An adversary could exploit this vulnerability by sending an unauthenticated HTTP request to the targeted device, thus causing a denial of service. 

**Multiple vulnerabilities in OAS Platform **

_Discovered by Jared Rittle._ 

Open Automation Software’s OAS Platform is an IoT gateway and protocol bus. It allows administrators to connect PLCs, devices, databases and custom apps. 

There are two vulnerabilities — TALOS-2024-1950 (CVE-2024-21870) and TALOS-2024-1951 (CVE-2024-22178) — that exist in the platform that can lead to arbitrary file creation or overwrite. An attacker can send a sequence of requests to trigger these vulnerabilities.  

An adversary could also send a series of requests to exploit TALOS-2024-1948 (CVE-2024-24976), but in this case, the vulnerability leads to a denial of service. 

An improper input validation vulnerability (TALOS-2024-1949/CVE-2024-27201) also exists in the OAS Engine User Configuration functionality that could lead to unexpected data in the configuration, including possible decoy usernames that contain characters not usually allowed by the software’s configuration. 

**Arbitrary write vulnerabilities in AMD graphics driver **

_Discovered by Piotr Bania._ 

There are two out-of-bounds write vulnerabilities in the AMD Radeon user mode driver for DirectX 11. TALOS-2023-1847 and TALOS-2023-1848 could allow an attacker with access to a malformed shader to potentially achieve arbitrary code execution after causing an out-of-bounds write. 

AMD graphics drivers are software that allows graphics processing units (GPUs) to communicate with the operating system.  

These vulnerabilities could be triggered from guest machines running virtualization environments to perform guest-to-host escape. Theoretically, an adversary could also exploit these issues from a web browser. Talos has demonstrated with past, similar, vulnerabilities that they could be triggered from HYPER-V guest using the RemoteFX feature, leading to executing the vulnerable code on the HYPER-V host.

Vulnerability in some TP-Link routers could lead to factory reset

Though April’s monthly security update from Microsoft includes 150 vulnerabilities, only three of them are considered “critical."

Tuesday, April 9, 2024 14:23

In one of the largest Patch Tuesdays in years, Microsoft disclosed 150 vulnerabilities across its software and product portfolio this week, including more than 60 that could lead to remote code execution. 

Though April’s monthly security update from Microsoft is the largest since at least the start of 2023, only three of the issues disclosed are considered “critical,” all of which are remote code execution vulnerabilities in Microsoft Defender for IoT.  

Most of the remainder of the security issues are considered “important,” and only two are “moderate” severity. 

The three critical vulnerabilities — CVE-2024-21322, CVE-2024-21323 and CVE-2024-29053 — are all remote code execution vulnerabilities in Microsoft Defender for IoT. Though little information is provided on how these issues could be exploited, Microsoft did state that exploitation of these vulnerabilities is “less likely.”  

There are also three vulnerabilities for which Microsoft said it had detected exploitation of the vulnerability in the wild: 

*   CVE-2024-26241: Elevation of privilege vulnerability in Win32k 
*   CVE-2024-28903: Security feature bypass vulnerability in Windows Secure Boot 
*   CVE-2024-28921: Security feature bypass vulnerability in Windows Secure Boot 

More than half of the code execution vulnerabilities exist in Microsoft SQL drivers. An attacker could exploit these vulnerabilities by tricking an authenticated user into connecting to an attacker-created SQL server via ODBC, which could result in the client receiving a malicious network packet. This could allow the adversary to execute code remotely on the client. 

A complete list of all the other vulnerabilities Microsoft disclosed this month is available on its update page. 

In response to these vulnerability disclosures, Talos is releasing a new Snort rule set that detects attempts to exploit some of them. Please note that additional rules may be released at a future date and current rules are subject to change pending additional information. Cisco Security Firewall customers should use the latest update to their ruleset by updating their SRU. Open-source Snort Subscriber Rule Set customers can stay up to date by downloading the latest rule pack available for purchase on Snort.org. 

The rules included in this release that protect against the exploitation of many of these vulnerabilities are 63254 - 63257, 63265 - 63271, 63274 and 63275. There are also Snort 3 rules 300873, 300874 and 300877 - 300879.

April’s Patch Tuesday includes 150 vulnerabilities, 60 which could lead to remote code execution

Cisco Talos is disclosing a new threat actor we deemed “Starry Addax” targeting mostly human rights activists, associated with the Sahrawi Arab Democratic Republic (SADR) cause with a novel mobile malware.

*   Cisco Talos is disclosing a new threat actor we deemed “Starry Addax” targeting mostly human rights activists associated with the Sahrawi Arab Democratic Republic (SADR) cause with a novel mobile malware. 
*   Starry Addax conducts phishing attacks tricking their targets into installing malicious Android applications we’re calling “FlexStarling.” 
*   For Windows-based targets, Starry Addax will serve credential-harvesting pages masquerading as login pages from popular media websites. 

_Talos would like to thank the Yahoo! Paranoids Advanced Cyber Threats Team for their collaboration in this investigation._ 

**Starry Addax has a special interest in Western Sahara**

The malicious mobile application (APK), “FlexStarling,” analyzed by Talos recently masquerades as a variant of the Sahara Press Service (SPSRASD) App. The Sahara Press Service is a media agency associated with the Sahrawi Arab Democratic Republic. The malware will serve content in the Spanish language from the SPSRASD website to look legitimate to the victim. However, in actuality, FlexStarling is a highly versatile malware capable of deploying additional malware components and stealing information from the infected devices. 

 Splash screen for the malicious application.

Starry Addax’s infrastructure can be used to target Windows- and Android-based users. This campaign's infection chain begins with a spear-phishing email sent to targets, consisting of individuals of interest to the attackers, especially human rights activists in Morocco and the Western Sahara region. The email contains content that requests the target to install the Sahrawi News Agency’s Mobile App or include a topical theme related to the Western Sahara.  

Some examples of the subject lines of the phishing emails consist of: 

طلب تثبيت التطبيق على هواتف متابعي وكالة الأنباء الصحراوية 

Request to install the application on the phones of Sahrawi News Agency followers 

الوفد برلماني الأوروبي يدلي بتصريحات 

The European Parliament delegation makes statements 

الوفد برلماني يدلي بتصريحات 

A parliamentary delegation makes statements 

عاجل وبالفيديو ونقلاً عن جريدة إلبايس 

Urgent, video, and quoted from El Pais newspaper 

The email originating from an attacker-owned domain, ondroid\[.\]site, consists of a shortened link to an attacker-controlled website and domain. Depending on the requestor’s operating system, the website will either serve the FlexStarling APK for Android devices or redirect the victim to a social media login page to harvest their credentials. The links observed by Talos so far are:  

www\[.\]ondroid\[.\]store/aL2mohh1 

www\[.\]ondroid\[.\]store/ties5shizooQu1ei/ 

**Starry Addax likely to escalate momentum **

Campaigns like this that target high-value individuals usually intend to sit quietly on the device for an extended period. All components from the malware to the operating infrastructure seem to be bespoke/custom-made for this specific campaign indicating a heavy focus on stealth and conducting activities under the radar. The use of FlexStarling with a Firebase-based C2 instead of commodity malware or commercially available spyware indicates the threat actor is making a conscious effort to evade detections and operate without being detected. 

The timelines connected to various artifacts used in the attacks indicate that this campaign is just starting and may be in its nascent stages with more infrastructure and Starry Addax working on additional malware variants. 

**FlexStarling – A highly capable implant **

The FlexStarling malware app requests a plethora of permissions from the Android OS to extract valuable information from the infected mobile device. The following list contains the permissions acquired by FlexStarling via its AndroidManifest\[.\]xml: 

Some of these permissions are dynamically requested at runtime: READ\_CALL\_LOG, READ\_EXTERNAL\_STORAGE, READ\_SMS, READ\_CONTACTS, WRITE\_EXTERNAL\_STORAGE, INTERNET, ACCESS\_NETWORK\_STATE, RECORD\_AUDIO, READ\_PHONE\_STATE. 

**Anti-emulation checks **

When the implant runs, it checks the BUILD information for keywords or phrases that indicate that it is running on an emulator or analysis tool. The implant checks for the following keywords: 

*   BUILD\[MANUFACTURER\] does not contain: “Genymotion”. 
*   BUILD\[MODEL\] does not contain any of: “google\_sdk”, “droid4x”, “Emulator”, "Android SDK built for x86" 
*   BUILD\[HARDWARE\] does not contains any of: “goldfish”, “vbox86”, “nox”. 
*   BUILD\[FingerPrint\] does not start with “generic”. 
*   BUILD\[Product\] does not consist of any of: “sdk”, “google\_sdk”, “sdk\_x86”, “vbox86p”, “nox”. 
*   BUILD\[Board\] does not contain: “nox”. 
*   BUILD\[Brand\] or Device does not start with “generic”.  

The implant also checks for the presence of the following emulation/virtualization-related files in the filesystem: 

*   /dev/socket/genyd 
*   /dev/socket/baseband\_genyd 
*   /dev/socket/qemud 
*   /dev/qemu\_pipe 
*   ueventd.android\_x86.rc 
*   X86.prop 
*   ueventd.ttVM\_x86.rc 
*   init.ttVM\_x86.rc 
*   fstab.ttVM\_x86 
*   fstab.vbox86 
*   init.vbox86.rc 
*   ueventd.vbox86.rc 
*   fstab.andy 
*   ueventd.andy.rc 
*   fstab.nox 
*   init.nox.rc 
*   Ueventd.nox.rc 

If none of the keywords or files are found or all checks are passed, the malicious app tries to gain permissions for managing external storage areas (shared storage space) on the device using the permission “MANAGE\_EXTERNAL\_STORAGE”.  The actor wants to gain the ability to read, write, modify, delete and manage files on external storage locations.  

**Stealing information and executing arbitrary code **

The malware obtains command codes and accompanying information from the C2 server. It then generates the MD5 hash string of the command code and compares its list of hardcoded hashes. The corresponding activity is carried out by the implant once a match is found. 

The various commands supported by the sample are: 

Command code MD5 hash 

Decode command code 

Intent 

801ab24683a4a8c433c6eb40c48bcd9d 

Download 

Download a file specified by a URL to the Downloads directory. 

e8606d021da140a92c7eba8d9b8af84f 

unknown 

Copy files from the download's directory to the application package directory 

725888549d44eb5a3a676c018df55943 

unknown 

Decrypt a dex file located in the application package directory and reflectively load it. 

3a884d7285b2caa1cb2b60f887571d6c 

unknown 

Cleanup directories – remove all files: 

*   Cache directory. 
    
*   Application package directory (including “/oat/”). 
    
*   External Cache Directory. 
    

f2a6c498fb90ee345d997f888fce3b18 

Delete 

Delete a specified filepath. 

3e679cff5b3a6f6f8f32aead541a0a12 

Drop 

Upload a local file to the attacker’s dropbox folders using the Dropbox API. 

The ACCESS TOKEN, local filepath and remote upload path is specified by the C2. 

fb84708d32d00fca5d352e460776584c 

DECRYPT 

AES Decrypt a file from the application package directory using the secret key and IV specified and write it to a file named “.EXEC.dex” 

0ba4439ee9a46d9d9f14c60f88f45f87 

check 

Check if a file inside the application package directory exists. 

These commands are supported by accompanying information and consist of the following variables being sent across by the C2: 

**DURL:** Indicates the download URL used by the “Download” command above. 

**APPNAME:** Indicates the filename to use for the destination file during the “Download” command. 

**DEX:** Contains the source file name to be used during the Decrypt (and reflectively load) commands. 

**ky1:** Indicates a value to be used in the context of specific command codes: 

*   Delete = File to be deleted. 
*   Drop = File to be read and uploaded to Dropbox. 
*   DECRYPT = Secret key used for AES decryption. 
*   Check = Filename to be whose presence is to be checked in the application package directory. 

 **ky2:** Indicates a value to be used in the context of specific command codes: 

*   Drop = Remote file location where the local file needs to be uploaded on Dropbox. 
*   DECRYPT = IV used for AES decryption. 

 **ky3:** Indicates a value to be used in the context of specific command codes: 

*   Drop = Dropbox ACCESS TOKEN value to be used during file upload. 
*   DECRYPT = IV used for AES decryption. 

 **fl:** Filename used during the DEX reflective load process.  

**ky4:** Used as a parameter during reflective loading of the DEX file. 

**ky5:** Secret key used for AES decryption as part of the implant’s DEX decrypt and reflective load. 

**ky6:** IV used for AES decryption as part of the implant’s DEX decrypt and reflective load. 

**ky7**: Contains the source file name to be used during the AES decryption as part of the implant’s DEX decrypt and reflective load. 

**Coverage **

Ways our customers can detect and block this threat are listed below. 

Cisco Secure Endpoint (formerly AMP for Endpoints) is ideally suited to prevent the execution of the malware detailed in this post. Try Secure Endpoint for free here. 

Cisco Secure Web Appliance web scanning prevents access to malicious websites and detects malware used in these attacks. 

Cisco Secure Email (formerly Cisco Email Security) can block malicious emails sent by threat actors as part of their campaign. You can try Secure Email for free here. 

Cisco Secure Firewall (formerly Next-Generation Firewall and Firepower NGFW) appliances such as Threat Defense Virtual, Adaptive Security Appliance and Meraki MX can detect malicious activity associated with this threat. 

Cisco Secure Malware Analytics (Threat Grid) identifies malicious binaries and builds protection into all Cisco Secure products. 

Umbrella, Cisco's secure internet gateway (SIG), blocks users from connecting to malicious domains, IPs and URLs, whether users are on or off the corporate network. Sign up for a free trial of Umbrella here. 

Cisco Secure Web Appliance (formerly Web Security Appliance) automatically blocks potentially dangerous sites and tests suspicious sites before users access them. 

Additional protections with context to your specific environment and threat data are available from the Firewall Management Center. 

 Cisco Duo provides multi-factor authentication for users to ensure only those authorized are accessing your network. 

 Open-source Snort Subscriber Rule Set customers can stay up to date by downloading the latest rule pack available for purchase on Snort.org. 

**IOCs **

IOCs for this research can also be found at our GitHub repository here. 

**Hashes **

f7d9c4c7da6082f1498d41958b54d7aeffd0c674aab26db93309e88ca17c826c 

ec2f2944f29b19ffd7a1bb80ec3a98889ddf1c097130db6f30ad28c8bf9501b3 

**Network IOCs **

hxxps\[://\]runningapplications-b7dae-default-rtdb\[.\]firebaseio\[.\]com 

ondroid\[.\]site 

ondroid\[.\]store 

bit\[.\]ly/48wdj1m 

www\[.\]ondroid\[.\]store/aL2mohh1 

bit\[.\]ly/48E4W3N 

www\[.\]ondroid\[.\]store/ties5shizooQu1ei/

Starry Addax targets human rights defenders in North Africa with new malware

An April 2023 study from Kent State University found that remote workers are more likely to be vigilant of security threats and take actions to ward them off than their in-office counterparts.

Thursday, April 4, 2024 14:00

As my manager knows, I’m not the biggest fan of working in a physical office. I’m a picky worker — I like my workspace to be borderline frigid, I hate dark mode on any software, and I want any and all lighting cranked all the way up.  

So, know that I’m biased going into this, but I also can’t get over the idea that companies are using cybersecurity as an excuse to create return-to-office policies in 2024.  

I started thinking about this because of the video game developer Rockstar, which owns some of the largest video game franchises on the planet like Red Dead Redemption and Grant Theft Auto. 

The company recently started asking its employees to return to its physical office five days a week in the name of productivity and security as the company pushes to finish its highly anticipated title “Grand Theft Auto VI.”  

Rockstar has long faced a number of cybersecurity concerns over the years, including a massive leak featuring early, in-progress gameplay of GTA VI in 2022 and other sensitive data. The attack was eventually attributed to the Lapsus$ group, and the perpetrator was eventually charged and sentenced. The first reveal trailer for the game was also leaked ahead of time.  

Many other companies have started to implement return-to-office policies over the past two years, citing various things ranging from worker productivity to interpersonal camaraderie, real estate costs, and more. I’m willing to hear arguments for all those things, but simply thinking that having employees all in one physical space is going to solve security problems seems far-fetched to me.  

We’ve written and talked about the various ways remote work has influenced cybersecurity since the onset of the COVID-19 pandemic. There’s no doubt that admins have had to implement new login methods, security controls and policies since more workers across the globe started working remotely. But four years into this trend, there’s no excuse to not be prepared to have remote workers anymore. 

An April 2023 study from Kent State University found that remote workers are more likely to be vigilant of security threats and take actions to ward them off than their in-office counterparts.  

The use of multi-factor authentication during the rise in remote work has skyrocketed, but often, this requirement is actually dropped if a user is physically in the office or accessing an on-site machine because of the perceived security of being in the office.  

The perceived security of a physical office can sometimes lull admins into a false sense of security, too, because machines located on-site may lack pre-boot authentication or encryption that’s commonly found on remote workers’ devices.  

I’m not saying that working in an office is inherently less secure than remote work, but I do believe that the risks are essentially the same. Regardless of where an employee is working from, they should be using app-based MFA to access all their services. Sensitive software and hardware should rely on passkeys or physical token access rather than outdated password policies that create easy-to-guess or shareable text-based passwords.  

And if security is the name of the game when asking employees to come back into the office, there’s still going to be a monetary investment that comes with that, too. 

Cisco’s recently published Global Hybrid Work study found that only 28 percent of responding employees say they would rank their employers’ office’s “Privacy and security features” as “very well.” To me, that says that even if employers want workers back in the office, they still need to upgrade their security, which is always going to mean more money and greater manpower.  

Security fundamentals should stay the same, no matter where your employees are. And suppose security is a chief concern for a company in wanting to go back to the “traditional” office lifestyle. In that case, I’m willing to bet they still have security gaps to overcome that simply can’t be solved by thinking they’ll be able to keep a closer eye on employees while they’re in the office to keep them from clicking on a phishing email. 

**The one big thing **

Remote system management/desktop access tools such as AnyDesk and TeamViewer have grown in popularity since 2020. While there are many legitimate uses for this software, adversaries are also finding ways to use them for command and control in their campaigns. Cisco Talos Incident Response (Talos IR) has recently seen a spike in actors using this type of software as a method of gaining initial access to a network or to spy on the actions of users. Talos IR noted in its Quarterly Trends report for the third quarter of 2023, “AnyDesk was observed in all ransomware and pre-ransomware engagements \[. . .\], underscoring its role in ransomware affiliates' attack chains.” 

**Why do I care? **

The use of these types of tools has increased since the start of the COVID-19 pandemic when remote work became more common. Since this software is legitimate, it can be easy for an attacker to compromise it and sit undetected on a network, bypassing traditional blocking methods. These tools introduce the ability for an adversary to potentially take full remote control of a system, are easy to download and install, and can be very difficult to detect since they are considered legitimate software. 

**So now what? **

Adopting one, or at most two, approved remote management solutions will allow the organization to thoroughly test and deploy in the most secure possible configuration. Once a solution is approved and championed for the organization, other remote management/access tools should be explicitly banned by policy. Due to the complexity of implementing all these controls, detection rules can serve as a backup in case an adversary finds a way to circumvent these mitigations. 

**Top security headlines of the week **

**The U.S. and Britain have jointly filed chargers and sanctions against a Chinese state-sponsored actor known as APT31.** The group is accused of a sweeping espionage campaign allegedly linked to China's Ministry of State Security (MSS) in the province of Hubei. The group reportedly targeted thousands of U.S. and foreign politicians, foreign policy experts and other high-profile targets. Individuals in the White House, U.S. State Department and spouses of officials were also among those targeted. The attacks aligned with geopolitical events affecting China, including economic tensions with the U.S., arguments over control of the South China Sea, and pro-democracy rallies in Hong Kong in 2019. A release from the U.S. Department of Justice stated that the campaigns involved more than 10,000 malicious emails, sent to targets in multiple continents, in what it called a “prolific global hacking operation.” The charges go on to say that APT31 hoped to compromise government institution networks and stealing trade secrets. Seven Chinese nationals are the target of the new sanctions for their alleged involvement with APT31, including the Wuhan XRZ corporation that is tied to the threat actor. (Reuters, U.S. Department of Justice) 

**A silent backdoor on Linux machines was almost a massive supply chain attack, before a lone developer found malicious code hidden in software updates.** The malicious code was hidden in two updates to xz Utils, an open-source data compression utility available on almost all installations of Linux and other Unix-like operating systems. Had it been successfully deployed, adversaries could have stashed malicious code in an SSH login certificate, upload it and execute it on the backdoored device. Whoever is behind this code likely spent years working on it, with open-source updates going back to 2021. The actor never actually took advantage of the malicious code, so it’s unclear what they planned to upload. Researchers eventually identified the vulnerability as CVE-2024-3094. The U.S. Cybersecurity and Infrastructure Security Agency warned government agencies to downgrade their xz Utils to older versions. (Ars Technica, Dark Reading) 

**There is a massive backup with the National Vulnerabilities Database and, consequently, MITRE is unable to compile a list of all new vulnerabilities.** A recent study from Flashpoint found that there was backlog of more than 100,000 vulnerabilities with no CVE number, and consequently, hadn’t been included in the NVD. Of those, 330 vulnerabilities had been exploited in the wild, yet defenders had not been made aware of them. The National Institute of Standards and Technology blamed the backup on an increase in the volume of software available to the public, leading to a larger number of vulnerabilities, as well as “a change in interagency support.” NIST has only analyzed about half of the more than 8,700 vulnerabilities that had been submitted so far in 2024. And in March alone, they only analyzed 199 out of the 3,370 vulnerabilities submitted. Several organizations have tried launching their own alternatives to the NVD, though adoption can still take a long time. NIST has also vowed to remain dedicated to the NVD and that it’s still regrouping its current efforts. (SecurityWeek, The Record by Recorded Future) 

**Can’t get enough Talos? **

*   Enterprise Imperatives: The Critical Importance of Threat Intelligence 
*   Beware the gap between security readiness and confidence levels, Cisco warns 

**Upcoming events where you can find Talos **

**Botconf** **(April 23 - 26)** 

_Nice, Côte d'Azur, France_

> _This presentation from Chetan Raghuprasad details the Supershell C2 framework. Threat actors are using this framework massively and creating botnets with the Supershell implants._

**CARO Workshop 2024** **(May 1 - 3)** 

_Arlington, Virginia_

> Over the past year, we’ve observed a substantial uptick in attacks by YoroTrooper, a relatively nascent espionage-oriented threat actor operating against the Commonwealth of Independent Countries (CIS) since at least 2022. Asheer Malhotra's presentation at CARO 2024 will provide an overview of their various campaigns detailing the commodity and custom-built malware employed by the actor, their discovery and evolution in tactics. He will present a timeline of successful intrusions carried out by YoroTrooper targeting high-value individuals associated with CIS government agencies over the last two years.

**RSA** **(May 6 - 9)** 

_San Francisco, California_    

**Most prevalent malware files from Talos telemetry over the past week **

**SHA 256:** a31f222fc283227f5e7988d1ad9c0aecd66d58bb7b4d8518ae23e110308dbf91    
**MD5:** 7bdbd180c081fa63ca94f9c22c457376   
**Typical Filename:** c0dwjdi6a.dll |  
**Claimed Product:** N/A    
**Detection Name:** Trojan.GenericKD.33515991 

**SHA 256:** 744c5a6489370567fd8290f5ece7f2bff018f10d04ccf5b37b070e8ab99b3241  
**MD5:** a5e26a50bf48f2426b15b38e5894b189  
**Typical Filename:** a5e26a50bf48f2426b15b38e5894b189.vir  
**Claimed Product:** N/A  
**Detection Name:** Win.Dropper.Generic::1201

**SHA 256:** 3a2ea65faefdc64d83dd4c06ef617d6ac683f781c093008c8996277732d9bd66  
**MD5:** 8b84d61bf3ffec822e2daf4a3665308c  
**Typical Filename:** RemComSvc.exe  
**Claimed Product:** N/A   
**Detection Name:** W32.3A2EA65FAE-95.SBX.TG

**SHA 256:** 0e2263d4f239a5c39960ffa6b6b688faa7fc3075e130fe0d4599d5b95ef20647   
**MD5:** bbcf7a68f4164a9f5f5cb2d9f30d9790   
**Typical Filename:** bbcf7a68f4164a9f5f5cb2d9f30d9790.vir   
**Claimed Product:** N/A   
**Detection Name:** Win.Dropper.Scar::1201 

**SHA 256:** 62dfe27768e6293eb9218ba22a3acb528df71e4cc4625b95726cd421b716f983  
**MD5:** 0211073feb4ba88254f40a2e6611fcef  
**Typical Filename:** UIHost64.exe  
**Claimed Product:** McAfee WebAdvisor  
**Detection Name:** Trojan.GenericKD.68726899

There are plenty of ways to improve cybersecurity that don’t involve making workers return to a physical office

Cisco Talos discovered a new threat actor we’re calling “CoralRaider” that we believe is of Vietnamese origin and financially motivated. CoralRaider has been operating since at least 2023, targeting victims in several Asian and Southeast Asian countries.

**CoralRaider targets victims’ data and social media accounts**

Thursday, April 4, 2024 08:00

*   Cisco Talos discovered a new threat actor we’re calling “CoralRaider” that we believe is of Vietnamese origin and financially motivated. CoralRaider has been operating since at least 2023, targeting victims in several Asian and Southeast Asian countries. 
*   This group focuses on stealing victims’ credentials, financial data, and social media accounts, including business and advertisement accounts.
*   They use RotBot, a customized variant of QuasarRAT, and XClient stealer as payloads in the campaign we analyzed.
*   The actor uses the dead drop technique, abusing a legitimate service to host the C2 configuration file and uncommon living-off-the-land binaries (LoLBins), including Windows Forfiles.exe and FoDHelper.exe 

**CoralRaider operators likely based in Vietnam **

Talos assesses with high confidence that the CoralRaider operators are based in Vietnam, based on the actor messages in their Telegram C2 bot channels and language preference in naming their bots, PDB strings, and other Vietnamese words hardcoded in their payload binaries. The actor’s IP address is located in Hanoi, Vietnam. 

 Our analysis revealed that the actor uses a Telegram bot, as a C2, to exfiltrate the victim’s data. This allowed us to collect information and uncover several invaluable indicators about the origin and activities of the attacker. 

The attacker used two Telegram bots: A “debug” bot for debugging, and an “online” bot where victim data was received. However, a Desktop image in the “debug” bot had a similar desktop and Telegram to the “online” bot. This showed that the actor possibly infected their own environment while testing the bot. 

Analyzing the images of the actor’s Desktop on the Telegram bot, we found a few Telegram groups in Vietnamese named “Kiém tien tử Facebook,” “Mua Bán Scan MINI,” and “Mua Bán Scan Meta.” Monitoring these groups revealed that they were underground markets where, among other activities, victim data was traded. 

In an image from the “debug bot,” we spotted the Windows device ID (HWID) and an IP address (118\[.\]71\[.\]64\[.\]18), located in Hanoi, Vietnam, that is likely to be CoralRaider’s IP address.

Talos’ research uncovered two other images that revealed a few folders on their OneDrive. One of the folders had a Vietnamese name, “Bot Export Chiến,” which is the same as one of the folders in the PDB strings of their loader component. Pivoting on the folder path in the PDB string, we discovered a few other PDB strings having similar paths but different Vietnamese names. We analyzed the discovered samples with the PDB strings and found they belong to the same loader family, RotBot. The Vietnamese name in the PDB string of the loader binary further strengthens our assessment that CoralRaider is of Vietnamese origin.

D:\\ROT\\ROT\\Build rot Export\\2024\\Bot Export Khuê\\14.225.210.XX-Khue-Ver 2.0\\GPT\\bin\\Debug\\spoolsv.pdb

D:\\ROT\\ROT\\Build rot Export\\2024\\Bot Export Trứ\\149.248.79.205 - NetFrame 4.5 Run Dll - 2024\\ChromeCrashServices\\obj\\Debug\\FirefoxCrashSevices.pdb

D:\\ROT\\ROT\\Build rot Export\\2024\\Bot Export Trứ\\139.99.23.9-NetFrame4.5-Ver2.0-Trứ\\GPT\\bin\\Debug\\spoolsv.pdb

  

D:\\ROT\\ROT\\Build rot Export\\2024\\Bot Export Chiến\\14.225.210.XX-Chiến -Ver 2.0\\GPT\\bin\\Debug\\spoolsv.pdb

  

D:\\ROT\\ROT\\Build rot Export\\2024\\Bot Export Trứ\\139.99.23.9-NetFrame4.5-Ver2.0-Trứ\\GPT\\bin\\Debug\\SkypeApp.pdb

  

D:\\ROT\\ROT\\Build rot Export\\2024\\Bot Export Chiến\\14.225.210.XX-Chiến -Ver 2.0\\GPT\\bin\\Debug\\spoolsv.pdb

  

D:\\ROT\\ROT\\ROT Ver 5.5\\Source\\Encrypted\\Ver 4.8 - Client Netframe 4.5\\XClient\\bin\\Debug\\AI.pdb

  

Another image we analyzed is an Excel spreadsheet that likely contained the victims’ data. We have redacted the images to maintain confidentiality. The spreadsheet has several tabs in Vietnamese, and their English translation showed us the tabs “Employee salary spreadsheet,” “advertising costs,” “website to buy copies,” “PayPal related,” and “can use.” The spreadsheet seemed to have multiple versions — the first was created on May 10, 2023. We also spotted that they have logged into their Microsoft Office 365 account with the display name “daloia krag” while accessing the spreadsheet, and CoralRaider likely operates the account. 

CoralRaider’s payload, XClient stealer analysis, showed us a few more indicators. CoralRaider had hardcoded Vietnamese words in several stealer functions of their payload XClient stealer. The stealer function maps the stolen victim’s information to hardcoded Vietnamese words and writes them to a text file on the victim machine’s temporary folder before exfiltration. One example function we observed is used to steal the victim’s Facebook Ads account that has hardcoded with Vietnamese words for Account rights, Threshold, Spent, Time Zone, and Date Created, etc.

**The campaign  **

Talos observed that CoralRaider is conducting a malicious campaign targeting victims in multiple countries in Asia and Southeast Asia, including India, China, South Korea, Bangladesh, Pakistan, Indonesia and Vietnam. 

The initial vector of the campaign is the Windows shortcut file. We are unclear on the technique the actor used to deliver the LNKs to the victims. Some of the shortcut file filenames that we observed during our analysis are:

*   자세한 비디오 및 이미지.lnk
*   設計內容+我的名片.lnk
*   run-dwnl-restart.lnk
*   index-write-upd.lnk
*   finals.lnk
*   manual.pdf.lnk
*   LoanDocs.lnk
*   DoctorReferral.lnk
*   your-award.pdf.lnk
*   Research.pdf.lnk
*   start-of-proccess.lnk
*   lan-onlineupd.lnk
*   refcount.lnk

We also discovered a few notable unique drive serial numbers from the metadata of the Windows Shortcut files:

*   A0B4-2B36
*   FA4C-C31D
*   94AA-CEFB
*   46F7-AF3B

The attack begins when a user opens a malicious Windows shortcut file, which downloads and executes an HTML application file (HTA) from an attacker-controlled download server. The HTA file executes an embedded obfuscated Visual Basic script. The malicious Visual Basic script executes an embedded PowerShell script in the memory, which decrypts and sequentially executes three other PowerShell scripts that perform anti-VM and anti-analysis checks, bypass the User Access Controls, disables the Windows and application notifications on the victim’s machine, and finally downloads and run the RotBot. 

RotBot, the QuasarRAT client variant, in its initial execution phase, performs several detection evasion checks on the victim machine and conducts system reconnaissance. RotBot then connects to a host on a legitimate domain, likely controlled by the threat actor, and downloads the configuration file for the RotBot to connect to the C2. CoralRaider uses the Telegram bot as the C2 channel in this campaign. 

After connecting to the Telegram C2, RotBot loads the payload XClient stealer onto the victim memory from its resource and runs its plugin program. The XClient stealer plugin performs anti-VM and anti-virus software checks on the victim's machine. It executes its functions to collect the victim's browser data, including cookies, stored credentials, and financial information such as credit card details. It also collects the victim’s data from social media accounts, including Facebook, Instagram, TikTok business ads, and YouTube. It also collects the application data from the Telegram desktop and Discord application on the victim's machine. The stealer plugin can capture screenshots of the victim’s desktop and save them as a PNG file in the victim's machine’s temporary folder. With PNG files, the stealer plugin dumps the collected victim’s data from the browser and social media accounts in a text file and creates a ZIP archive. The PNG and ZIP files are exfiltrated to the attacker's Telegram bot C2.

Infection flow diagram.

**RotBot loads and runs the payload  **

RotBot, a remote access tool (RAT) compiled on Jan. 9, 2024, is downloaded and runs on the victim machine disguised as a Printer Subsystem application “spoolsv.exe.” RotBot is a variant of the QuasarRAT client that the threat actor has customized and compiled for this campaign. 

During its initial execution, RotBot performs several checks on the victim’s machine to evade detection, including IP address, ASN number, and running processes of the victim’s machine. It performs reconnaissance of system data on the victim machine. It also configures the internet proxy on the victim machine by modifying the registry key: 

Software\\Microsoft\\Windows\\CurrentVersion\\Internet 

Settings with the values:

ProxyServer = 127.0.0.1:80

ProxyEnable = 1

We observed that RotBot discovered in this campaign creates mutex in the victim machine as the infection markers​​ using the hardcoded strings in the binary.

RotBot loads and runs the XClient stealer module from its resources and uses the configuration parameters for its Telegram C2 bot from the downloaded configuration file. 

The XClient stealer sample we analyzed in this campaign is a .Net executable compiled on Jan. 7, 2024. It has extensive information-stealing capability through its plugin module and various modules for performing remote administrative tasks. 

XClient stealer has three primary functions that help it to avoid the radar. First, it will do virtual environment evasion if the victim’s machine runs in VMware or VirtualBox. It also checks if a DLL called sbieDll.dll exists in the victim machine file system to detect if it runs in the Sandboxie environment. XClient stealer also checks if anti-virus software, including AVG, Avast, and Kaspersky, is running on the victim’s machine. 

After bypassing all the checking functions, the XClient stealer captures the victim’s machine screenshot, saves it with the “.png” extension in the victim’s temporary user profile folder, and sends it to C2 through the URL “/sendPhoto.” 

XClient stealer steals victims’ social media web application credentials, browser data, and financial information such as credit card details. It targets Chrome, Microsoft Edge, Opera, Brave, CocCoc, and Firefox browser data files through the absolute paths of the respective browser installation paths. It extracts the contents of the browser database to a text file in the victim’s profile local temporary folder. 

XClient stealer hijacks and steals various Facebook data from the victim’s Facebook account. It sets custom HTTP header metadata along with the victim’s stolen Facebook cookie, and the username sends requests to Facebook APIs through the URLs below.

It checks if the victim’s Facebook is a business or ads account and uses regular expressions to search for access\_token, assetID, and paymentAccountID. Using Facebook graph API, XClient attempts to collect an extensive list of information from the victim’s account, shown in the table below.

Entities

Value place holders

facebook\_pages

verification\_status, fan\_count, followers\_count, is\_owned, name, is\_published,is\_promotable, parent\_page, promotion\_eligible, has\_transitioned\_to\_new\_page\_experience, picture, roles

Adaccounts, businesses

name, permitted\_roles, can\_use\_extended\_credit, primary\_page, wo\_factor\_type, client\_ad\_accounts, verification\_status, id, created\_time, is\_disabled\_for\_integrity\_reasons, sharing\_eligibility\_status, allow\_page\_management\_in\_www, timezone\_id, timezone\_offset\_hours\_utc

owned\_ad\_accounts

id, currency, timezone\_offset\_hours\_utc, timezone\_name,adtrust\_dsl

Business\_users

name, account\_status, account\_id, owner\_business, created\_time, next\_bill\_date, currency, timezone\_name, timezone\_offset\_hours\_utc, business\_country\_code, disable\_reason, adspaymentcycle{threshold\_amount}, has\_extended\_credit, adtrust\_dsl, funding\_source\_details, balance, is\_prepay\_account, owner

XClient stealer also collects the financial information from the victims’ Facebook business and ads accounts.

Payment related entities

Value Place holders

pm\_credit\_card

display\_string, exp\_month, exp\_year, is\_verified

payment\_method\_direct\_debits

address, can\_verify, display\_string, s\_awaiting, is\_pending,

status

payment\_method\_paypal

email\_address

payment\_method\_tokens

Current\_balance, original\_balance, time\_expire, type

amount\_spent, userpermissions

user, role

 Using the graph API, XClient stealer retrieves victims’ account friend list details and pictures. 

XClient stealer also targets the victim’s Instagram account and YouTube accounts through the URLs and collects various information, including username, badge\_count, appID, accountSectionListRenderer, contents, title, data, actions, getMultiPageMenuAction, menu, multiPageMenuRenderer, sections and hasChannel. It collects the application data from the Telegram desktop and Discord application on the victim’s machine. XClient also collects the data from the victim’s TikTok business account and checks for business ads. 

Talos compiled the hardcoded HTTP request header metadata the XClient stealer uses in this campaign while retrieving the victim’s information from Facebook, Instagram, and YouTube accounts. 

Facebook

*   sec-ch-ua-mobile: ?0
    
*   sec-ch-ua-platform: \\"Windows\\"
    
*   sec-fetch-dest: document
    
*   sec-fetch-mode: navigate
    
*   sec-fetch-site: none
    
*   sec-fetch-user: ?1
    
*   upgrade-insecure-requests: 1
    
*   user-agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36
    
*   sec-ch-ua: \\"Not?A\_Brand\\";v=\\"8\\", \\"Chromium\\";v=\\"108\\", \\"Google Chrome\\";v=\\"108\\"
    
*   sec-ch-ua-mobile: ?0
    

  

Instagram

*   Sec-Ch-Prefers-Color-Scheme: light
    
*   Sec-Ch-Ua: "Google Chrome"; v = "113", "Chromium"; v = "113", "Not-A.Brand"; v = "24"
    
*   Sec-Ch-Ua-Full-Version-List: "Google Chrome"; v = "113.0.5672.127", "Chromium"; v = "113.0.5672.127", "Not-A.Brand"; v = "24.0.0.0"
    
*   Sec-Ch-Ua-Mobile: ?0
    
*   Sec-Ch-Ua-Platform: "Windows"
    
*   Sec-Ch-Ua-Platform-Version: "10.0.0"
    
*   Sec-Fetch-Dest: document
    
*   Sec-Fetch-Mode: navigate
    
*   Sec-Fetch-Site: none
    
*   Sec-Fetch-User: ?1
    
*   Upgrade-Insecure-Requests: 1
    
*   User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit / 537.36(KHTML, like Gecko) Chrome / 113.0.0.0 Safari / 537.36
    

  

Youtube

*   content-type: application/json
    
*   sec-ch-ua: "Google Chrome";v="113", "Chromium";v="113", "Not-A.Brand";v="24"
    
*   sec-ch-ua-arch: "x86"
    
*   sec-ch-ua-bitness: "64"
    
*   sec-ch-ua-full-version: "113.0.5672.127"
    
*   sec-ch-ua-full-version-list: "Google Chrome";v="113.0.5672.127", "Chromium";v="113.0.5672.127", "Not-A.Brand";v="24.0.0.0"
    
*   sec-ch-ua-mobile: ?0
    
*   sec-ch-ua-model: ""
    
*   sec-ch-ua-platform: "Windows"
    
*   sec-ch-ua-platform-version: "10.0.0"
    
*   sec-ch-ua-wow64: ?0
    
*   sec-fetch-dest: empty
    
*   sec-fetch-mode: same-origin
    
*   user-agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/113.0.0.0 Safari/537.36
    
*   x-goog-authuser: 0
    
*   x-origin: https://www.youtube.com
    
*   x-youtube-bootstrap-logged-in: true
    
*   x-youtube-client-name: 1
    

Finally, the XClient stealer stores the victim’s social media data, which is collected into a text file in the local user profile temporary folder and creates a ZIP archive. The ZIP files were exfiltrated to the Telegram C2 through the URL “/sendDocument”.

Talos’ research of this campaign focused on discovering and disclosing a new threat actor of Vietnamese origin and their payloads. Additional technical details of the attack chain components of this campaign can be found in the report published by the researchers at QiAnXin Threat Intelligence Center. 

**Coverage**

Cisco Secure Endpoint (formerly AMP for Endpoints) is ideally suited to prevent the execution of the malware detailed in this post. Try Secure Endpoint for free here.

Cisco Secure Web Appliance web scanning prevents access to malicious websites and detects malware used in these attacks.

Cisco Secure Email (formerly Cisco Email Security) can block malicious emails sent by threat actors as part of their campaign. You can try Secure Email for free here.

Cisco Secure Firewall (formerly Next-Generation Firewall and Firepower NGFW) appliances such as Threat Defense Virtual, Adaptive Security Appliance and Meraki MX can detect malicious activity associated with this threat.

Cisco Secure Malware Analytics (Threat Grid) identifies malicious binaries and builds protection into all Cisco Secure products.

Umbrella, Cisco's secure internet gateway (SIG), blocks users from connecting to malicious domains, IPs and URLs, whether users are on or off the corporate network. Sign up for a free trial of Umbrella here.

Cisco Secure Web Appliance (formerly Web Security Appliance) automatically blocks potentially dangerous sites and tests suspicious sites before users access them.

Additional protections with context to your specific environment and threat data are available from the Firewall Management Center.

Cisco Duo provides multi-factor authentication for users to ensure only those authorized are accessing your network.

Open-source Snort Subscriber Rule Set customers can stay up to date by downloading the latest rule pack available for purchase on Snort.org. Snort SID for this threat is 63192.

ClamAV detections are also available for this threat:

Lnk.Downloader.CoralRaider-10024620-0

Html.Downloader.CoralRaider-10025101-0

Win.Trojan.RotBot-10024631-0

Win.Infostealer.XClient-10025106-2

**Indicators of Compromise**

Indicators of Compromise associated with this threat can be found here.

CoralRaider targets victims’ data and social media accounts

While there are many legitimate uses for this software, adversaries are also finding ways to use them for command and control in their campaigns.

Tuesday, April 2, 2024 08:00

*   Remote system management/desktop access tools such as AnyDesk and TeamViewer have grown in popularity since 2020. While there are many legitimate uses for this software, adversaries are also finding ways to use them for command and control in their campaigns.
*   There is no easy way to effectively block all unauthorized remote management tools, but security can be greatly improved through a combination of policy and technical controls.
*   Early warning alerts can be configured to alert defenders to remote management software activity that may have circumvented the technical controls.

**The remote management/access software problem**

Since 2020, the use of remote system management/access tools such as AnyDesk and TeamViewer has exploded in popularity due to forced work-from-home during the COVID-19 pandemic.

Whether used by an IT help desk technician to fix a user’s remote system or by co-workers for collaboration, these tools play an essential role in most corporations’ digital functions. However, this convenience comes at a cost. These tools introduce the ability for an adversary to potentially take full remote control of a system, are easy to download and install, and can be very difficult to detect since they are considered legitimate software. 

Further complicating the task of recognizing the malicious use of these tools, many organizations struggle to combat “shadow IT” in which individual users or overly proactive IT personnel might install unauthorized remote management tools to accomplish a benign goal.

Cisco Talos Incident Response (Talos IR) is seeing adversaries capitalize on this opportunity in the wild. We recently noted in our Quarterly Trends report for the third quarter of 2023, “AnyDesk was observed in all ransomware and pre-ransomware engagements \[. . .\], underscoring its role in ransomware affiliates' attack chains.”

While AnyDesk is a legitimate application, it highlights the tremendous value that can be gained through a security program that intentionally focuses on preventing unauthorized use of these tools. Talos is referencing AnyDesk for the purposes of this blog post, but any remote management tool is at risk of these exploits. There are several policy changes, technical countermeasures and security alerts that admins and defenders can use to ensure that AnyDesk, and similar pieces of software, are only used for legitimate purposes when deployed.

Adopting one, or at most two, approved remote management solutions will allow the organization to thoroughly test and deploy in the most secure possible configuration.

If possible, integration with other organizational technology such as Active Directory or multi-factor authentication (MFA) will provide additional layers of protection and verification. Tying the approved remote management solutions into these already structured security solutions can make it easier to build “early warning” detections and alerts around unauthorized connectivity and use.

Once a solution is approved and championed for the organization, other remote management/access tools should be explicitly banned by policy. Ideally, this should be accompanied by a software inventory audit and published guidance on approved/non-approved software for the organization. Training and consistent enforcement of this policy will help reduce the “shadow IT” noise in the environment and leave network defenders with more time to investigate true anomalies.

**Technical controls**

While very worthwhile, preventing unauthorized use of these tools is not simple. First, the scores of commercially available remote access tools make it difficult to address every option an adversary might use. Many of those tools are frequently updated, meaning that blocking the executables by their hash value is not as effective. 

Adversaries also commonly rename the executables, meaning that filename blocks aren’t going to be helpful, either. 

Many popular solutions operate over common ports and protocols, such as ports 80 and 443, making them difficult to block at the firewall, and remote access tool creators often decline to publish their central server IP addresses due to frequently changing resolutions, which limits the effectiveness of static IP address blocks. A combination of approaches and techniques is necessary to limit the opportunity for an adversary to use remote access/management tools in any given environment.

**DNS security controls**

One of the most effective methods for detecting, and sometimes blocking, the activities of unauthorized remote management/access software, is by auditing and blocking DNS queries associated with these tools.

If your organization uses Cisco Umbrella for DNS security, it’s fairly easy to review and block DNS queries related to unauthorized traffic.

To review what might already be on your network, log into the Umbrella console and view “Reporting > App Discovery > Unreviewed Apps,” filtered by the “Collaboration” and “IT Services Management” categories, this is an excellent starting point to identify unexpected remote access software.

Simply clicking “Block this app” gives the administrator the ability to block future DNS requests associated with any particular result. If you prefer to take an even more proactive approach, going to “Policies > Policy Components > Application Settings” allows you to search all applications currently categorized by Umbrella, whether they have been seen on your network or not, and block them by policy. Again, the “Collaboration” and “IT Services Management” categories should be the areas of focus for policy review.

As with all of these technical controls, there are a few limitations. The first major caveat is that this only works if the DNS queries are evaluated by your security stack. In the case of DNS traffic from a home user’s system not traveling over the corporate network, the activity would be invisible. The second major caveat is that some remote management software has direct peer-to-peer capabilities, meaning the software might not send a DNS query to an easily identifiable domain when initiating a connection. 

**Firewall controls**

While less scalable and reliable, basic IP address blocking can be beneficial for preventing unauthorized remote software connections. Some vendors list static IP addresses for their central servers on their support sites that can be leveraged to control this access. However, many vendor IP addresses change periodically, making the task a bit challenging.

Another potentially fruitful approach to firewall traffic blocking is by port number. For example, TeamViewer prefers to use port 5938, although it can fall back on the practically unblockable port 443. While blocking port 5938 would not stop the connection, a properly configured alert would provide defenders with an early warning that TeamViewer was trying to connect out.

Some firewalls also provide additional functionality around session content, similar to Umbrella’s capabilities. Firewalls such as Cisco’s Meraki provide an allow/block URL listing that can be configured to prevent connectivity to unapproved remote management software sites. Cisco Meraki can provide content filtering options that may be helpful in blocking remote management/access sites.

Administrators should consider that firewall controls to combat unauthorized remote software management connections can have unintended consequences and should be heavily tested and piloted prior to implementation.

Verify that IP addresses are dedicated to that application prior to blocking in order to avoid blocking Content Delivery Network (CDN) nodes or other cloud computing shared resources. 

Finally, network segmentation or micro-segmentation can be useful in blocking unauthorized remote management software usage. For instance, categorizing and organizing server resources separate from workstation resources can allow for more tailored options around blocking all unnecessary traffic at the firewall, include that which may be associated with remote management tools. Some organizations already do this well by integrating with group policy configurations.

**Host-based controls****Windows Defender Application Control (WDAC) and AppLocker**

Of all the controls discussed in this post, WDAC and AppLocker are the only ones that can offer almost 100 percent protection against unauthorized remote management/access software execution.

In their most secure configuration, which allows only pre-approved software to run, users or adversaries can't run unexpected executables. However, this comes at a cost, as the approved software baseline maintenance level of effort can be high, and the user experience can be very limited if they are not allowed to install applications as needed.

WDAC and AppLocker offer considerable flexibility in their policies, so some organizations choose to only lock down their critical servers, such as domain controllers, which leaves user system policies more flexible. This approach has benefits far beyond simply blocking remote access/management software, as it will stop most malware from executing, as well.

Keep in mind that, while WDAC is currently more difficult to configure, it has more advanced capabilities and Microsoft is positioning it as the replacement for AppLocker. At the moment, AppLocker is receiving security updates, but no new feature updates.

**Registry filename blocks**

It is possible to block remote management/access software execution by filename via a registry “DisallowRun” key. However, Talos IR does not recommend this approach, except as a containment measure during incident response, since it is not scalable as a preventative measure and is trivially easy to bypass by renaming the executable or modifying the registry. 

**EDR blocks**

Almost every modern EDR can block file hashes, which gives defenders the capability to block the hashes associated with remote management/access software installers and/or installed executables. However, similarly to the filename GPO blocks, this is not scalable or reliable as a proactive measure, since every new version of every software distribution will have a new hash value. This measure should be restricted to containment during incident response only. 

Some EDR solutions offer methods to block vulnerable or unauthorized software, albeit with significant caveats regarding the limitations of those capabilities. The authors of this article have not tested those capabilities but note them here for the sake of completeness.

**Host-based firewalls**

The recommendations for host-based firewall rules are much the same as standalone firewalls, covered above. These can be useful where administrators expect users to roam outside of the boundary of the corporate network, such as home workers off the corporate VPN or using a split-tunnel VPN implementation. 

**Administrator permission restriction**

Restricting administrator permissions so that most users cannot conduct administrator actions on their work computer, such as installing remote access/management software, can help limit an adversary’s ability to install this software after the initial compromise.

Applying the principle of least privilege, which includes both locking down local administrator permissions and limiting the permissions of users’ domain accounts, is considered standard best practice.

**NAC controls**

While network access control (NAC) solutions do not directly block the use of remote management software, they can ensure that all other technical controls are working properly before admitting an endpoint to the network. If the device is a rogue system or lacks EDR, for example, NAC would prevent it from joining.

Another benefit offered by a NAC solution is software version enforcement through custom rules. In Cisco ISE, for example, there are Posture Checks. Organizations can use this to ensure that only the approved version(s) of their approved remote management tool are allowed on the network, directly addressing the threat of an adversary introducing an older version of the approved solution to the network for malicious purposes.

**Alerts and forensics**

Due to the complexity of implementing all these controls, detection rules can serve as a backup in case an adversary finds a way to circumvent the previous mitigations we discussed. The possibilities for these “tripwire” detections are endless, and SOCs/threat-hunting teams should continuously think of ways to improve them, but some ideas are listed below.

**Central log collection**

The first prerequisite for any successful detections is to have centralized log aggregation. At the very minimum, this should ingest firewall logs, EDR alerts and Windows Event logs for key servers. 

**SIEM alerts for suspicious strings**

Setting up a simple alert that triggers upon observation of strings associated with unauthorized remote access/management software product names (e.g., “AnyDesk”) can be an effective way to proactively identify unexpected product installations that were not otherwise blocked.

For example, an MSI installation would generate an Event 11707 entry in the Windows Application Event logs containing the software product name. If the SIEM were ingesting and evaluating those event logs, it would fire an alert, thereby alerting the SOC to a potential installation. This rule would need to be tuned to avoid excessive false positives, but it could result in a valuable early detection method. 

**SIEM alerts for firewall blocks on unique ports**

Enhanced alerting may be necessary to draw a SOC’s attention to firewall blocks associated with remote management/access traffic. Firewalls continuously block traffic, generally dropping thousands or millions of packets per hour. With that in mind, SOCs are not alerted every time a firewall rule drops traffic — especially if the rule that drops the traffic is the Implicit Deny rule blocking all traffic that was not specifically allowed. However, if an internal host attempts to communicate over a port dedicated to remote access/management software, that might merit attention from the SOC. 

It's worth considering creating an SIEM rule that alerts on any firewall block event involving outbound traffic to certain key ports, for example, 5938 (associated with TeamViewer). That alert, while an indication that the network blocks are working as intended, would be a good indication that the SOC needs to investigate the system originating the traffic.

The level of effort required to properly secure remote management/access software is daunting. However, the frequency of use by adversaries makes that effort a necessity. In the wrong hands, these tools serve as a ready-made command and control mechanism. If an organization can afford to secure its VPN solution, it should almost certainly devote resources to locking down unauthorized remote management software, as well.