CVE-2013-2002 in libXt
Summary
by MITRE
Buffer overflow in X.org libXt 1.1.3 and earlier allows X servers to cause a denial of service (crash) and possibly execute arbitrary code via crafted length or index values to the _XtResourceConfigurationEH function.
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Analysis
by VulDB Data Team • 05/14/2021
The vulnerability identified as CVE-2013-2002 represents a critical buffer overflow flaw within the X.org libXt library version 1.1.3 and earlier implementations. This vulnerability specifically affects the _XtResourceConfigurationEH function which handles resource configuration events within X Window System servers. The flaw arises from inadequate input validation when processing crafted length or index values that are passed to this function during normal operation. The buffer overflow condition occurs when the application fails to properly bounds-check user-supplied data before copying it into fixed-size memory buffers, creating a scenario where malicious input can overwrite adjacent memory locations and potentially corrupt program execution flow.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to write beyond the allocated buffer boundaries. The exploitation of this flaw can result in two primary outcomes: denial of service through system crashes and potential code execution privileges. When an X server processes malformed resource configuration data, the buffer overflow can cause the application to terminate abnormally, leading to service disruption. However, in more sophisticated attack scenarios, the overflow may allow attackers to overwrite critical program memory structures, potentially enabling arbitrary code execution with the privileges of the affected X server process. This makes the vulnerability particularly dangerous in environments where X server processes run with elevated permissions or where multiple users share the same system resources.
The operational impact of CVE-2013-2002 extends beyond simple service interruption to encompass broader security implications within graphical user interface environments. X Window System servers are fundamental components in Unix-like operating systems, providing the foundation for graphical interfaces and desktop environments. When compromised, this vulnerability can affect entire desktop sessions and potentially provide attackers with persistent access to user workstations. The vulnerability is particularly concerning in multi-user environments where attackers might leverage this flaw to gain unauthorized access to graphical sessions, especially when combined with other exploitation techniques that could escalate privileges. The flaw affects systems running vulnerable versions of libXt, which is widely distributed across various Unix and Linux distributions, making the potential attack surface extensive.
Mitigation strategies for this vulnerability should prioritize immediate patching of affected systems to upgrade to libXt versions that contain proper bounds checking and input validation. System administrators should implement comprehensive monitoring for unusual X server behavior and network traffic patterns that might indicate exploitation attempts. The implementation of address space layout randomization and stack canaries can provide additional defense-in-depth measures, though these protections are not foolproof against well-crafted exploits. Security teams should also consider implementing network segmentation to limit the potential impact of successful exploitation, particularly in enterprise environments where X server processes might be exposed to untrusted network traffic. Additionally, regular security assessments should verify that all X server components are updated to versions that have been tested against known vulnerabilities, as this particular flaw represents a classic example of how insufficient input validation can create severe security risks in system-level software components. The vulnerability demonstrates the importance of proper software quality assurance practices and the necessity of thorough code review processes for critical system libraries that handle untrusted input data.