CVE-2011-1485 in PolicyKit
Summary
by MITRE
Race condition in the pkexec utility and polkitd daemon in PolicyKit (aka polkit) 0.96 allows local users to gain privileges by executing a setuid program from pkexec, related to the use of the effective user ID instead of the real user ID.
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Analysis
by VulDB Data Team • 09/03/2024
The vulnerability identified as CVE-2011-1485 represents a critical race condition flaw within the PolicyKit framework, specifically affecting the pkexec utility and polkitd daemon in version 0.96. This issue arises from the improper handling of user identity during privilege escalation operations, creating a window where malicious actors can exploit the system's security model. The flaw is particularly dangerous because it leverages the setuid mechanism that is fundamental to how privilege escalation works in Unix-like systems, making it a prime target for local privilege escalation attacks.
The technical root cause of this vulnerability lies in the use of effective user ID (EUID) instead of real user ID (RUID) when processing authentication requests within the pkexec utility. During the execution of pkexec, the system should verify the identity of the actual user requesting privileges, but due to the race condition, it incorrectly relies on the effective user ID which may have been modified by other processes. This design flaw creates a temporal window where an attacker can manipulate the process environment to bypass authentication checks. The race condition occurs when the pkexec utility performs a series of operations that depend on the user's identity, but the timing allows for interference between these operations.
The operational impact of this vulnerability is severe for any system running PolicyKit 0.96 or earlier versions, as it provides local users with a straightforward path to escalate their privileges to root level. Attackers can exploit this weakness by carefully crafting execution sequences that take advantage of the race condition window, potentially allowing them to execute arbitrary code with elevated privileges. This vulnerability directly violates the principle of least privilege and undermines the entire security architecture that PolicyKit is designed to enforce. The attack vector is particularly insidious because it requires no network connectivity and can be executed locally, making it difficult to detect through traditional network monitoring systems.
This vulnerability maps to CWE-362, which specifically addresses Race Conditions, and aligns with several techniques documented in the MITRE ATT&CK framework under privilege escalation tactics. The flaw demonstrates how improper handling of process identity can be exploited to bypass security controls, making it relevant to ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation." The use of setuid programs as attack vectors is a well-documented pattern in exploit development, and this particular vulnerability shows how the interaction between different system components can create unexpected security weaknesses. Organizations running affected versions of PolicyKit should immediately implement mitigations including updating to patched versions, applying system hardening measures, and monitoring for suspicious privilege escalation attempts. The vulnerability also highlights the importance of proper privilege management and the need for careful consideration of identity handling in security-critical system components.