CVE-2004-2012 in NetBSD
Summary
by MITRE
The systrace_exit function in the systrace utility for NetBSD-current and 2.0 before April 16, 2004, and certain FreeBSD ports, does not verify the owner of the /dec/systrace connection before setting euid to 0, which allows local users to gain root privileges.
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Analysis
by VulDB Data Team • 08/15/2024
The systrace utility in NetBSD and certain FreeBSD systems contained a critical privilege escalation vulnerability that allowed local attackers to execute arbitrary code with root privileges. This vulnerability resided in the systrace_exit function which failed to properly validate the ownership of the /dev/systrace connection before performing a critical privilege elevation operation. The flaw existed in versions of NetBSD-current and 2.0 prior to the April 16, 2004 security patch, as well as in various FreeBSD ports that incorporated the affected code.
The technical implementation of this vulnerability stems from inadequate access control mechanisms within the systrace utility's exit handling routine. When the systrace_exit function was invoked, it would automatically set the effective user ID to zero without first confirming that the calling process had proper authorization to perform this operation. This design flaw created a privilege escalation path where any local user could manipulate the systrace connection to gain root privileges, effectively bypassing the operating system's security model. The vulnerability directly relates to CWE-276, which addresses improper privilege management, and represents a classic example of insufficient authorization checks in security-critical code paths.
The operational impact of this vulnerability was severe as it enabled any local user to escalate their privileges to root level without requiring any special authentication or administrative credentials. Attackers could exploit this weakness to gain complete control over affected systems, potentially leading to unauthorized data access, system compromise, and persistent backdoor installation. The vulnerability was particularly dangerous because it required no network connectivity and could be exploited from within the system itself, making it difficult to detect through traditional network-based monitoring systems. This type of local privilege escalation attack aligns with ATT&CK technique T1068, which covers privilege escalation through local exploitation of system vulnerabilities.
The exploitation of this vulnerability required minimal technical knowledge and could be accomplished through simple local commands that manipulated the systrace connection. System administrators were particularly vulnerable because the attack could be launched from any user account with access to the system, and the lack of proper access controls meant that even non-root users could potentially exploit this flaw. The vulnerability also highlighted the importance of proper privilege separation and access control validation in system utilities, as the systrace utility was designed for security monitoring but contained a flaw that undermined its own security model. Organizations running affected versions of NetBSD or FreeBSD were strongly advised to apply the relevant security patches immediately and implement additional monitoring to detect potential exploitation attempts. The vulnerability demonstrated the critical need for thorough security auditing of system utilities and the importance of proper privilege management in operating system components, particularly those designed to enforce security policies.