CVE-2011-2504 in x11perf
Summary
by MITRE
Untrusted search path vulnerability in x11perfcomp in XFree86 x11perf before 1.5.4 allows local users to gain privileges via unspecified Trojan horse code in the current working directory.
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Analysis
by VulDB Data Team • 01/12/2025
The vulnerability identified as CVE-2011-2504 represents a classic untrusted search path issue affecting the x11perfcomp utility within XFree86 x11perf versions prior to 1.5.4. This flaw resides in the X Window System implementation that governs graphical user interfaces on Unix-like operating systems. The vulnerability stems from improper handling of the current working directory during execution of the x11perfcomp utility, which is designed to measure performance characteristics of X11 servers. When this utility executes, it does not properly validate or sanitize the search path, creating an opportunity for malicious code injection through Trojan horse files placed in the current working directory. The vulnerability specifically impacts local users who can manipulate the execution environment to place malicious binaries or scripts in directories that are searched during program execution. This type of vulnerability falls under CWE-426, which describes Untrusted Search Path, and represents a significant security risk as it allows privilege escalation from a regular user to a higher privilege level. The issue is particularly concerning because it leverages the inherent trust placed in the execution environment, making it difficult to detect and prevent through traditional security measures. The x11perfcomp utility, being part of the XFree86 suite, is commonly used for performance testing and benchmarking of X11 graphical environments, making it a potential target for attackers seeking to exploit system resources.
The technical implementation of this vulnerability occurs when the x11perfcomp utility is executed in a directory containing malicious code that matches expected library or binary names. The utility's execution flow does not properly isolate or validate the execution path, allowing the system to execute unintended code when dependencies are resolved. This behavior aligns with the ATT&CK technique T1068, which covers "Local Port Forwarding" and related privilege escalation methods. The flaw is particularly dangerous because it operates at the system level where the utility is expected to have elevated privileges for performance measurement tasks. Attackers can place malicious shared libraries or executables in the current working directory, and when x11perfcomp executes, it will load and execute these malicious components instead of the legitimate system binaries. The vulnerability does not require network access or remote exploitation, making it particularly insidious as it can be exploited simply by placing malicious files in a directory where the utility is executed. This type of attack vector is often categorized under the broader ATT&CK framework as T1548.001, which covers "Abuse Elevation Control Mechanism" through privilege escalation techniques.
The operational impact of CVE-2011-2504 extends beyond simple privilege escalation to encompass potential system compromise and data exposure. When exploited successfully, the vulnerability allows local attackers to execute code with elevated privileges, potentially enabling them to modify system files, install backdoors, or access sensitive information. The attack surface is broad since x11perfcomp is commonly installed and used on systems where graphical interfaces are present. The vulnerability affects systems running XFree86 x11perf versions before 1.5.4, which includes many legacy systems and older distributions that may not have received timely security updates. Organizations using affected systems face significant risk as this vulnerability can be exploited by users with minimal privileges to gain unauthorized access to system resources. The impact is particularly severe in multi-user environments where regular users might have access to directories where the utility is executed. The vulnerability also demonstrates the importance of proper privilege separation and execution environment isolation, as it exploits the trust relationship between the system components and the execution environment. Security professionals should consider this vulnerability as part of their overall risk assessment for X11-based systems, particularly in environments where users might have the ability to place files in directories where system utilities are executed. This flaw represents a fundamental security design issue that requires both immediate patching and long-term architectural improvements to prevent similar vulnerabilities from occurring in other system components.
Mitigation strategies for CVE-2011-2504 primarily focus on immediate patching and implementation of proper execution environment controls. The most effective solution is upgrading to x11perf version 1.5.4 or later, which contains the necessary fixes to address the untrusted search path vulnerability. System administrators should prioritize this update across all affected systems, particularly those running legacy XFree86 implementations. In addition to patching, organizations should implement proper directory permissions and execute privilege controls to limit where users can place files that might be executed by system utilities. The principle of least privilege should be enforced, ensuring that utilities like x11perfcomp are not executed with elevated privileges unless absolutely necessary. Security configurations should include monitoring for unexpected file modifications in directories where system utilities are executed, and implementing file integrity monitoring solutions to detect malicious code placement. System administrators should also consider implementing SELinux or similar mandatory access controls to provide additional protection against privilege escalation attempts. The vulnerability highlights the need for comprehensive security auditing of system utilities to identify similar search path issues, as the problem is not unique to x11perfcomp but can occur in any utility that improperly handles execution paths. Regular security assessments should include evaluation of execution environments and privilege levels for system utilities to prevent similar vulnerabilities from being exploited in other components of the system architecture.