CVE-2021-33845: Splunk User Enumeration Attempt

Try in Splunk Security Cloud

Description

On May 3rd, 2022, Splunk published a security advisory for username enumeration stemming from verbose login failure messages present on some REST endpoints. This detection will alert on attempted exploitation in patched versions of Splunk as well as actual exploitation in unpatched version of Splunk.

• Type: TTP

• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

• Last Updated: 2022-04-29

• Author: Lou Stella, Splunk

• ID: 25625cb4-1c4d-4463-b0f9-7cb462699cde

AnnotationsATT&CK

ID

Technique

Tactic

T1078

Valid Accounts

Defense Evasion, Initial Access, Persistence, Privilege Escalation

Kill Chain Phase

• Reconnaissance

NIST

• DE.CM

CIS20

• CIS 3
• CIS 5
• CIS 16

CVESearch

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 `splunkd_failed_auths` 
| stats count(user) as auths by user, src 
| where auths>5 
| stats values(user) as "Users", sum(auths) as TotalFailedAuths by src 
| `splunk_user_enumeration_attempt_filter`

Macros

The SPL above uses the following Macros:

• splunkd_failed_auths

Note that splunk_user_enumeration_attempt_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

• user
• src
• info
• action

How To Implement

This detection does not require you to ingest any new data. The detection does require the ability to search the _audit index. This detection may assist in efforts to find password spraying or brute force authorization attempts in addition to someone enumerating usernames.

Known False Positives

Automation executing authentication attempts against your Splunk infrastructure with outdated credentials may cause false positives.

Associated Analytic story

• Splunk Vulnerabilities

RBA

Risk Score

Impact

Confidence

Message

40.0

50

80

$TotalFailedAuths$ failed authentication events to Splunk from $src$ detected.

Reference

• https://www.splunk.com/en_us/product-security/announcements/svd-2022-0502.html

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

• https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1078/splunkd_auth/audittrail.log

source | version: 1