CVE-2013-1990 in libXvMC
Summary
by MITRE
Multiple integer overflows in X.org libXvMC 1.0.7 and earlier allow X servers to trigger allocation of insufficient memory and a buffer overflow via vectors related to the (1) XvMCListSurfaceTypes and (2) XvMCListSubpictureTypes functions.
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Analysis
by VulDB Data Team • 05/14/2021
The vulnerability identified as CVE-2013-1990 represents a critical security flaw within the X.org libXvMC library version 1.0.7 and earlier implementations. This issue affects the X Window System's video acceleration subsystem where the XvMC (X Video Motion Compensation) extension provides hardware-accelerated video decoding capabilities. The vulnerability stems from improper input validation mechanisms within the library's handling of surface and subpicture type listing operations, creating a scenario where malicious X servers can manipulate memory allocation processes through crafted function calls.
The technical exploitation of this vulnerability occurs through integer overflow conditions in the XvMCListSurfaceTypes and XvMCListSubpictureTypes functions. When these functions process user-supplied parameters, they fail to properly validate integer values before performing memory allocation calculations. This allows an attacker to manipulate the size calculations used for buffer allocation, resulting in insufficient memory being allocated for data structures. The subsequent buffer overflow occurs when the system attempts to write data beyond the allocated memory boundaries, potentially leading to arbitrary code execution or system instability.
From an operational impact perspective, this vulnerability creates significant risks for systems utilizing X Window System environments with video acceleration capabilities. Attackers with access to an X server can leverage this flaw to execute malicious code with the privileges of the X server process, potentially leading to complete system compromise. The vulnerability affects the core X server functionality and can be exploited remotely if the X server is configured to accept connections from untrusted networks. This represents a particularly dangerous scenario in multi-user environments or networked systems where X11 forwarding is enabled.
The vulnerability aligns with CWE-190, Integer Overflow or Wraparound, which specifically addresses issues where integer arithmetic results in values that exceed the maximum representable value for the data type. Additionally, this flaw maps to ATT&CK technique T1059.007 for Command and Scripting Interpreter: Python, though more directly related to T1203, Exploitation for Client Execution, and T1068, Exploitation of Remote Services. The memory corruption aspect of this vulnerability also relates to T1070, Indicator Removal on Host, as exploitation may involve overwriting memory regions that could contain security-related data structures.
Mitigation strategies for CVE-2013-1990 should focus on immediate patching of the libXvMC library to versions 1.0.8 or later where integer overflow protections have been implemented. System administrators should also implement network segmentation to limit access to X servers and disable unnecessary X11 forwarding capabilities. Additional protective measures include monitoring for unusual memory allocation patterns and implementing strict input validation for X server connections. Organizations should also consider disabling XvMC functionality entirely if it is not required for their specific use cases, as this eliminates the attack surface associated with this vulnerability. Regular security audits of X server configurations and network access controls remain essential for maintaining defense-in-depth posture against similar vulnerabilities.