Microsoft Security Response Center

**What privileges could an attacker gain?** An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.

**Why is the MITRE Corporation the assigning CNA (CVE Numbering Authority)?** CVE-2022-23960 is regarding a vulnerability known as Spectre-BHB. MITRE created this CVE on behalf of Arm Limited. Please see Spectre-BHB on arm Developer for more information.

**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.

**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.

**What privileges could be gained by an attacker who successfully exploited the vulnerability?** An attacker who successfully exploited the vulnerability could replace Microsoft-shipped code with their own code, which would then be run as root in the context of a Guest Configuration daemon. On an Azure VM with the Guest Configuration Linux Extension installed, this would run in the context of the GC Policy Agent daemon. On an Azure Arc-enabled server, it could run in the context of the GC Arc Service or Extension Service daemons.

**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.

**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.

**What privileges could an attacker gain?** An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.

**In what scenarios is my computer vulnerable?** For Windows 11 and Windows 10 the FAX service is not installed by default. For the vulnerability to be exploitable, the Windows Fax and Scan feature needs to be enabled, and the Fax service needs to be running. Systems that do not have the Fax service running are not vulnerable. **How can I verify whether the Fax service is running?** 1. Hold the **Windows key** and press **R** on your keyboard. This will open the Run dialog. 2. Type _services.msc_ and press **Enter** to open the Services window. 3. Scroll through the list and locate the **Fax** service. * If the Fax service is not listed, Windows Fax and Scan is not enabled and the system is not vulnerable. * If the Fax service is listed but the status is not _Running_, then the system is not vulnerable at the time, but could be targeted if the service was started. The update should be installed as soon as possible or the Fax service should be removed if not needed.

**According to the CVSS metric, user interaction is required (UI:R). What interaction would the user have to do?** Exploitation of the vulnerability requires that a user open a specially crafted file. * In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and convincing the user to open the file. * In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) containing a specially crafted file designed to exploit the vulnerability. An attacker would have no way to force users to visit the website. Instead, an attacker would have to convince users to click a link, typically by way of an enticement in an email or instant message, and then convince them to open the specially crafted file.