CVE-2005-4352 in Linux
Summary
by MITRE
The securelevels implementation in NetBSD 2.1 and earlier, and Linux 2.6.15 and earlier, allows local users to bypass time setting restrictions and set the clock backwards by setting the clock ahead to the maximum unixtime value (19 Jan 2038), which then wraps around to the minimum value (13 Dec 1901), which can then be set ahead to the desired time, aka "settimeofday() time wrap."
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Analysis
by VulDB Data Team • 08/01/2017
The vulnerability described in CVE-2005-4352 represents a critical design flaw in the time setting mechanisms of operating systems, specifically affecting NetBSD versions 2.1 and earlier, as well as Linux kernels 2.6.15 and earlier. This issue stems from the implementation of securelevels, which are security measures designed to prevent unauthorized modification of system time. The flaw exploits the fundamental limitations of 32-bit signed integer representations for Unix timestamps, creating an unintended path for privilege escalation and time manipulation attacks.
The technical exploitation of this vulnerability relies on the mathematical properties of 32-bit signed integer arithmetic and the specific implementation of the settimeofday() system call. When a local user attempts to set the system clock to the maximum value representable by a 32-bit signed integer, which occurs on January 19, 2038, the timestamp value wraps around due to integer overflow. This wraparound produces the minimum representable value of approximately December 13, 1901, effectively creating a time warp that bypasses the security restrictions imposed by securelevels. The vulnerability is classified under CWE-191, Integer Underflow, and more specifically CWE-190, Integer Overflow, as it exploits the boundary conditions of integer representations.
The operational impact of this vulnerability extends beyond simple time manipulation, as it fundamentally undermines the security model of time-based access controls and authentication mechanisms. Systems relying on securelevels for time protection become vulnerable to attacks that can manipulate system clocks to bypass time-sensitive security checks, potentially enabling privilege escalation attacks, log manipulation, and circumvention of time-based authentication systems. This vulnerability directly relates to ATT&CK technique T1070.004, Indicator Removal on Host, as attackers can manipulate timestamps to hide malicious activities or bypass time-based security controls. The ability to set the clock backwards also affects system logging, audit trails, and cryptographic timestamp validation, creating potential for broader security breaches.
Mitigation strategies for CVE-2005-4352 focus on both immediate system updates and architectural improvements to time handling mechanisms. The primary solution involves upgrading to patched versions of affected operating systems where the securelevels implementation has been corrected to properly validate time values before allowing modifications. Additionally, system administrators should implement strict access controls and monitoring for time-setting operations, as the vulnerability requires local user access to exploit. The fix typically involves modifying the settimeofday() system call to properly detect and reject time values that would cause integer overflow or wraparound conditions, ensuring that time manipulation remains within reasonable bounds and maintains the security guarantees of the securelevels mechanism. Organizations should also consider implementing time synchronization protocols like NTP with proper authentication to prevent unauthorized time modifications and maintain system integrity.