CVE-2022-46343 in X11 Server
Summary
by MITRE • 12/15/2022
A vulnerability was found in X.Org. This security flaw occurs because the handler for the ScreenSaverSetAttributes request may write to memory after it has been freed. This issue can lead to local privileges elevation on systems where the X server is running privileged and remote code execution for ssh X forwarding sessions.
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Analysis
by VulDB Data Team • 11/15/2024
The vulnerability identified as CVE-2022-46343 resides within the X.Org server implementation, specifically within the ScreenSaverSetAttributes request handler. This flaw represents a classic use-after-free vulnerability that stems from improper memory management practices within the X server's processing pipeline. The X.Org server serves as the foundational graphics server for Unix-like operating systems and X Window System implementations, making this vulnerability particularly concerning given the widespread deployment of X11 across various computing environments.
The technical nature of this vulnerability manifests when the X server processes the ScreenSaverSetAttributes request, which is part of the X11 protocol extension for managing screen savers and power management features. During this processing, the server allocates memory for handling the request parameters and subsequently frees this memory before all references to it have been properly resolved. This creates a window where the memory location may be accessed or overwritten by subsequent operations, leading to potential arbitrary code execution or privilege escalation. The vulnerability is classified under CWE-416 as Use After Free, a well-documented weakness that frequently results in system compromise due to the predictable nature of memory corruption attacks.
The operational impact of CVE-2022-46343 extends beyond simple local privilege escalation to encompass remote code execution capabilities through SSH X forwarding sessions. When an X server runs with elevated privileges, particularly in environments where users might have access to the display server, attackers can exploit this vulnerability to gain root-level access to the system. The remote execution aspect becomes particularly dangerous in SSH environments where X11 forwarding is enabled, as attackers can leverage the vulnerability through network connections without requiring physical access to the target system. This threat model aligns with ATT&CK technique T1068 which covers Exploitation for Privilege Escalation, and T1071.004 which covers Application Layer Protocol: SSH.
Systems most at risk include enterprise environments running X.Org servers with elevated privileges, particularly those with X11 forwarding enabled for remote administration. The vulnerability affects various Linux distributions and Unix-like systems that utilize the X.Org server implementation, with the severity increasing in environments where users have access to privileged X server processes. Organizations running servers with active X11 sessions, especially those used for remote administration or development work, face significant exposure. The exploitability of this vulnerability is enhanced by the fact that X11 forwarding is commonly enabled in SSH configurations, making it a prime target for remote attackers who can leverage network-based attacks to compromise systems. Mitigation strategies should focus on immediate patching of X.Org server implementations, disabling unnecessary X11 forwarding in SSH configurations, and implementing network segmentation to limit access to privileged X server instances.