CVE-2013-2005 in libXt
Summary
by MITRE
X.org libXt 1.1.3 and earlier does not check the return value of the XGetWindowProperty function, which allows X servers to trigger use of an uninitialized pointer and memory corruption via vectors related to the (1) ReqCleanup, (2) HandleSelectionEvents, (3) ReqTimedOut, (4) HandleNormal, and (5) HandleSelectionReplies functions.
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Analysis
by VulDB Data Team • 05/14/2021
The vulnerability identified as CVE-2013-2005 resides within the X.org libXt library version 1.1.3 and earlier, representing a critical security flaw that undermines the integrity of X Window System client applications. This issue stems from inadequate error handling mechanisms within the library's implementation of XGetWindowProperty function calls, creating a scenario where malicious X servers can exploit the absence of proper return value validation to induce memory corruption and potential arbitrary code execution. The vulnerability specifically affects functions responsible for request cleanup, selection event handling, timeout management, normal request processing, and selection reply handling, all of which operate within the X11 protocol implementation layer that governs graphical user interfaces in Unix-like operating systems.
The technical exploitation of this vulnerability occurs through a classic uninitialized pointer dereference attack pattern where the libXt library fails to verify whether XGetWindowProperty operations complete successfully before proceeding with subsequent memory operations. When an X server sends crafted requests containing malformed window property data, the library's failure to check the function's return status results in the use of uninitialized memory locations, leading to unpredictable behavior including memory corruption, application crashes, or potentially remote code execution. This flaw operates at the intersection of CWE-457 Uninitialized Variable and CWE-822 Untrusted Pointer Dereference, creating a dangerous combination where malformed input data can be processed without proper validation, allowing attackers to manipulate memory layout and execution flow.
The operational impact of this vulnerability extends across multiple X11 client applications that depend on libXt for window management and event handling functionality, including but not limited to window managers, desktop environments, and graphical applications running on Linux and Unix systems. Attackers exploiting this vulnerability can potentially gain elevated privileges through local or remote X server connections, particularly when applications are running with elevated permissions or when the X server is configured to accept connections from untrusted networks. The attack surface is particularly concerning in multi-user environments where X11 forwarding is enabled, as it allows remote attackers to execute arbitrary code on target systems without requiring direct physical access. This vulnerability aligns with ATT&CK technique T1068 Exploitation for Privilege Escalation and T1059 Command and Scripting Interpreter, as it enables attackers to leverage the X11 protocol to execute malicious code through compromised applications.
Mitigation strategies for CVE-2013-2005 primarily involve immediate patching of affected libXt library versions to ensure proper return value validation for XGetWindowProperty function calls, with administrators advised to upgrade to libXt 1.1.4 or later versions that contain the necessary fixes. System administrators should also implement X11 access controls through proper firewall configurations and X11 access control lists to restrict unauthorized connections to X servers, particularly when X11 forwarding is enabled for remote connections. Additionally, monitoring X11 server logs for suspicious activity and implementing network segmentation can help detect and prevent exploitation attempts. The vulnerability demonstrates the critical importance of proper error handling in security-sensitive libraries and underscores the need for comprehensive input validation and return value checking in all system components that interface with external data sources, particularly those operating in multi-user or networked environments where security boundaries may be less defined.