CVE-2011-2905 in Linux
Summary
by MITRE
Untrusted search path vulnerability in the perf_config function in tools/perf/util/config.c in perf, as distributed in the Linux kernel before 3.1, allows local users to overwrite arbitrary files via a crafted config file in the current working directory.
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Analysis
by VulDB Data Team • 12/29/2021
The vulnerability identified as CVE-2011-2905 represents a critical untrusted search path issue within the Linux kernel's performance monitoring tools. This flaw exists in the perf_config function located in tools/perf/util/config.c, which is part of the perf utility suite that provides system performance analysis capabilities. The vulnerability affects all Linux kernel versions prior to 3.1, making it a significant concern for systems running older kernel versions. The core issue stems from how the perf utility handles configuration file processing, specifically when it searches for configuration files in the current working directory without proper validation of the file's origin or authenticity.
The technical implementation of this vulnerability allows local attackers to exploit a privilege escalation vector through careful manipulation of the configuration file search process. When perf attempts to load configuration settings, it does not properly validate the source of configuration files, enabling an attacker to place a maliciously crafted config file in the current working directory. This malicious file can then be loaded by perf, potentially causing the utility to overwrite arbitrary files on the system. The vulnerability operates through a classic path traversal or search path manipulation attack pattern that has been documented in various security frameworks and represents a direct violation of secure coding practices for file handling operations.
The operational impact of this vulnerability extends beyond simple file overwriting, as it can be leveraged for more sophisticated attacks within the local system environment. An attacker with access to a user account can exploit this vulnerability to overwrite critical system files, modify configuration settings, or potentially escalate privileges depending on how perf is executed within the system. The attack requires local system access and knowledge of the perf utility's behavior, but the potential consequences are significant since perf is commonly used for performance monitoring and analysis on development systems and servers. This vulnerability particularly affects systems where perf is run with elevated privileges or where users have the ability to execute perf in contexts that could be manipulated by an attacker.
Mitigation strategies for this vulnerability focus on both immediate patching and operational security measures. The primary solution is to upgrade to Linux kernel version 3.1 or later, where the vulnerability has been addressed through proper validation of configuration file sources. Organizations should implement comprehensive patch management procedures to ensure all systems are updated promptly. Additionally, security practitioners should consider implementing file system permissions and access controls to limit where configuration files can be written, particularly in directories where perf or similar utilities might be executed. The vulnerability aligns with CWE-276, which addresses improper file permissions, and can be mapped to ATT&CK technique T1068, which covers local privilege escalation through exploitation of system vulnerabilities. System administrators should also consider implementing monitoring for unusual file creation patterns in directories where perf utilities are commonly executed, as this could indicate exploitation attempts.