Microsoft Security Response Center

**What security feature could be bypassed by this vulnerability?** An attacker who successfully exploited this vulnerability could bypass Secure Boot.

**How could an attacker exploit the vulnerability?** A remote code execution vulnerability exists in the way that the Microsoft Server Message Block 3.1.1 (SMBv3) protocol handles certain requests. An attacker who successfully exploited the vulnerability could gain the ability to execute code on the target system. This vulnerability can be exploited through two different vectors: * **For the vulnerability to be exploited on the SMB Client**, an unauthenticated attacker would first need to configure a malicious SMBv3 server and convince a user to connect to it by enticing them to click a specially crafted link. * \*\*For the vulnerability to be exploited on the SMB Server \*\*, an authenticated attacker could send specially crafted packets from an SMB Client to a targeted SMBv3 Server.

**Are there any more actions I need to take to be protected from this vulnerability?** Yes. Customers vulnerable to this issue would need to enable Extended Protection in order to prevent this attack. For more information, see Exchange Server Support for Windows Extended Protection **Is there more information available about this release of Exchange Server?** For more information on this issue, please see The Exchange Blog.

**Are there any more actions I need to take to be protected from this vulnerability?** Yes. Customers vulnerable to this issue would need to enable Extended Protection in order to prevent this attack. For more information, see Exchange Server Support for Windows Extended Protection **Is there more information available about this release of Exchange Server?** For more information on this issue, please see The Exchange Blog.

**Are there any more actions I need to take to be protected from this vulnerability?** Yes. Customers vulnerable to this issue would need to enable Extended Protection in order to prevent this attack. For more information, see Exchange Server Support for Windows Extended Protection **Is there more information available about this release of Exchange Server?** For more information on this issue, please see The Exchange Blog.

**Are there any more actions I need to take to be protected from this vulnerability?** Yes. Customers vulnerable to this issue would need to enable Extended Protection in order to prevent this attack. For more information, see Exchange Server Support for Windows Extended Protection **Is there more information available about this release of Exchange Server?** For more information on this issue, please see The Exchange Blog.

**Are there any more actions I need to take to be protected from this vulnerability?** Yes. Customers vulnerable to this issue would need to enable Extended Protection in order to prevent this attack. For more information, see Exchange Server Support for Windows Extended Protection **Is there more information available about this release of Exchange Server?** For more information on this issue, please see The Exchange Blog.

**What privileges could be gained by an attacker who successfully exploited the vulnerability?** An attacker would only be able to delete targeted files on a system. They would not gain privileges to view or modify file contents.

**What security feature could be bypassed by this vulnerability?** An attacker who successfully exploited this vulnerability could bypass Secure Boot.

**According to the CVSS metric, the attack vector is local (AV:L). Why does the CVE title indicate that this is a remote code execution?** The word **Remote** in the title refers to the location of the attacker. This type of exploit is sometimes referred to as Arbitrary Code Execution (ACE). The attack itself is carried out locally. For example, when the score indicates that the **Attack Vector** is **Local** and **User Interaction** is **Required**, this could describe an exploit in which an attacker, through social engineering, convinces a victim to download and open a specially crafted file from a website which leads to a local attack on their computer.