CVE-2005-1768 in Linux
Summary
by MITRE
Race condition in the ia32 compatibility code for the execve system call in Linux kernel 2.4 before 2.4.31 and 2.6 before 2.6.6 allows local users to cause a denial of service (kernel panic) and possibly execute arbitrary code via a concurrent thread that increments a pointer count after the nargs function has counted the pointers, but before the count is copied from user space to kernel space, which leads to a buffer overflow.
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Analysis
by VulDB Data Team • 07/03/2019
The vulnerability described in CVE-2005-1768 represents a critical race condition within the Linux kernel's ia32 compatibility layer, specifically affecting the execve system call implementation. This flaw exists in kernel versions prior to 2.4.31 and 2.6.6, creating a temporal window where concurrent thread execution can exploit a pointer counting mechanism during process execution. The race condition occurs when a secondary thread increments a pointer count after the nargs function has already counted the pointers but before the count is securely transferred from user space to kernel space, resulting in a dangerous buffer overflow scenario that can compromise system stability and security.
The technical exploitation of this vulnerability relies on the fundamental timing issue within the kernel's pointer management system. During execve operations, the kernel must accurately count the number of arguments and environment variables passed to a new process. When a local user creates a concurrent thread that modifies the pointer count in the interim period between the initial counting phase and the secure copying of data from user space, the kernel's buffer management becomes compromised. This creates a situation where the kernel attempts to allocate memory based on an incorrect count, leading to buffer overflow conditions that can trigger kernel panics or potentially allow privilege escalation through arbitrary code execution.
The operational impact of this vulnerability extends beyond simple denial of service, as it represents a potential path to system compromise. The kernel panic resulting from the buffer overflow can cause complete system crashes, disrupting service availability and potentially providing attackers with opportunities to exploit the system during recovery processes. The possibility of arbitrary code execution through this race condition places the entire system at risk, as local users could leverage this vulnerability to gain elevated privileges and potentially establish persistent access to affected systems. This vulnerability particularly affects systems running older kernel versions where the race condition window remains unpatched, making it a significant concern for organizations maintaining legacy infrastructure.
Mitigation strategies for CVE-2005-1768 primarily focus on immediate kernel version updates to patched releases. System administrators should prioritize upgrading to kernel versions 2.4.31 or 2.6.6 and later, which contain the necessary fixes for the race condition in the ia32 compatibility code. Additionally, implementing proper access controls and limiting local user privileges can reduce the attack surface for exploitation attempts. The vulnerability aligns with CWE-362, which identifies race conditions as a critical weakness in concurrent programming, and relates to ATT&CK technique T1068, which covers privilege escalation through local exploitation. Organizations should also consider implementing monitoring solutions to detect anomalous thread behavior and potential exploitation attempts, while maintaining comprehensive system backups to ensure rapid recovery from any successful attacks that may occur.