CVE-2006-2916 in Linux
Summary
by MITRE
artswrapper in aRts, when running setuid root on Linux 2.6.0 or later versions, does not check the return value of the setuid function call, which allows local users to gain root privileges by causing setuid to fail, which prevents artsd from dropping privileges.
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Analysis
by VulDB Data Team • 06/21/2019
The vulnerability described in CVE-2006-2916 resides within the artswrapper component of aRts, which is part of the Advanced Linux Sound Architecture suite. This flaw represents a critical privilege escalation vulnerability that directly impacts systems where aRts is installed with setuid root permissions. The vulnerability specifically affects Linux kernel versions 2.6.0 and later, making it relevant to a substantial portion of enterprise and desktop Linux environments from that era. The core issue manifests in the improper handling of privilege management within the sound system's wrapper process.
The technical flaw occurs when the artswrapper process executes with elevated privileges due to its setuid root configuration but fails to properly validate the return value of the setuid function call. This function is responsible for changing the effective user ID of the process from root to a less privileged user. When the setuid call fails, the process continues to run with root privileges instead of dropping them as intended. The vulnerability exploits the assumption that setuid operations will succeed, creating a persistent root privilege escalation vector. This behavior violates fundamental security principles of privilege separation and least privilege enforcement.
The operational impact of this vulnerability is severe as it enables local attackers to gain root access on compromised systems without requiring additional exploitation techniques. Attackers can simply cause the setuid system call to fail through various means such as resource exhaustion, system call interference, or by manipulating the execution environment. Once successful, the attacker gains complete system control, allowing for arbitrary code execution, data exfiltration, and persistence establishment. This vulnerability essentially undermines the security model of the entire sound subsystem, as it provides a direct path to root privileges from any local user account.
Mitigation strategies for CVE-2006-2916 include immediate patching of the aRts package to ensure proper return value checking of setuid calls, implementing proper privilege dropping mechanisms, and removing unnecessary setuid permissions from sound system components. System administrators should also consider disabling unused sound services and implementing mandatory access controls through tools like SELinux or AppArmor. The vulnerability aligns with CWE-250, which addresses "Execute Code with Unusual or Unconventional Program Flow," and relates to ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation." Additionally, this issue demonstrates the importance of proper error handling in security-critical code paths and the necessity of comprehensive privilege management validation in Unix-like operating systems.