CVE-2005-3181 in Linux
Summary
by MITRE
The audit system in Linux kernel 2.6.6, and other versions before 2.6.13.4, when CONFIG_AUDITSYSCALL is enabled, uses an incorrect function to free names_cache memory, which prevents the memory from being tracked by AUDITSYSCALL code and leads to a memory leak that allows attackers to cause a denial of service (memory consumption).
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Analysis
by VulDB Data Team • 06/10/2019
The vulnerability described in CVE-2005-3181 represents a critical memory management flaw within the Linux kernel's audit subsystem that emerged in kernel versions prior to 2.6.13.4. This issue specifically affects systems where the CONFIG_AUDITSYSCALL configuration option is enabled, which activates the kernel's auditing capabilities for system calls. The audit system serves as a crucial security mechanism that tracks and logs system call activities, making it essential for compliance monitoring and security incident response. When enabled, this subsystem maintains detailed records of process activities and system interactions, creating a comprehensive audit trail for security analysis and forensic investigations.
The technical root cause of this vulnerability lies in the improper memory deallocation function being used within the audit system's name_cache management code. Specifically, the kernel employs an incorrect function to free memory allocated for the names_cache structure, which is responsible for storing and managing cached names of system call arguments. This memory management error prevents the audit subsystem from properly tracking the freed memory through its auditing mechanisms. The flaw creates a memory leak condition where allocated memory blocks are not correctly accounted for by the audit system's memory tracking code, leading to gradual memory consumption over time.
The operational impact of this vulnerability extends beyond simple resource exhaustion, as it fundamentally compromises the integrity of the audit system's memory management. Attackers can exploit this weakness by triggering repeated system call operations that utilize the affected name_cache functionality, causing the kernel to consume increasing amounts of memory without proper accounting. This memory consumption pattern can eventually lead to system instability, performance degradation, or complete denial of service conditions where the system becomes unresponsive due to memory exhaustion. The vulnerability is particularly concerning because it operates at the kernel level, making it difficult to detect and mitigate without proper system monitoring and kernel updates.
This vulnerability aligns with CWE-401, which categorizes improper handling of memory allocation and deallocation issues, and demonstrates how kernel-level memory management errors can be exploited for denial of service attacks. The flaw also intersects with ATT&CK technique T1490, which covers resource exhaustion attacks that consume system resources to deny service to legitimate users. Organizations running affected kernel versions face significant operational risks as this vulnerability can be exploited by both malicious actors seeking to disrupt services and by automated tools designed to probe system weaknesses. The memory leak behavior creates a stealthy attack vector that may not immediately manifest as system failure but gradually degrades performance until the system becomes unusable.
The recommended mitigation strategy involves upgrading to kernel versions 2.6.13.4 or later, where the memory deallocation function has been corrected to properly handle the names_cache memory management. System administrators should prioritize patching affected systems, particularly those running audit-enabled configurations, as the vulnerability can be exploited without requiring special privileges or authentication. Additionally, monitoring systems should be implemented to track memory consumption patterns and identify anomalous behavior that may indicate exploitation attempts. Organizations should also consider implementing memory monitoring tools that can detect unusual memory allocation patterns and alert security teams to potential exploitation of similar memory management vulnerabilities within their kernel environments.