CVE-2005-0178 in Linux
Summary
by MITRE
Race condition in the setsid function in Linux before 2.6.8.1 allows local users to cause a denial of service (crash) and possibly access portions of kernel memory, related to TTY changes, locking, and semaphores.
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Analysis
by VulDB Data Team • 07/01/2019
The vulnerability described in CVE-2005-0178 represents a critical race condition within the Linux kernel's setsid function affecting systems prior to version 2.6.8.1. This flaw specifically manifests during the process of creating a new session and controlling terminal, where concurrent access to shared kernel resources creates unpredictable behavior that can lead to system instability. The race condition occurs when multiple processes attempt to manipulate terminal session control simultaneously, exploiting the lack of proper synchronization mechanisms in the kernel's TTY subsystem.
The technical implementation of this vulnerability involves the improper handling of kernel memory structures during session establishment operations. When the setsid function executes, it must manage several critical kernel components including terminal locking mechanisms, semaphore management, and process group associations. The race condition arises because the function does not adequately synchronize access to these shared resources, allowing for a scenario where one process may modify kernel data structures while another process is in the middle of accessing the same structures. This creates a window where the kernel's internal state becomes inconsistent, potentially leading to memory corruption or invalid memory access patterns that cause system crashes.
The operational impact of this vulnerability extends beyond simple denial of service to potentially expose sensitive kernel memory contents to local users. While the primary effect manifests as system crashes and kernel oops messages, the underlying race condition creates opportunities for information disclosure attacks where attackers might be able to read portions of kernel memory that should remain protected. This represents a significant security risk as it could potentially allow local users to extract sensitive information about kernel memory layout, process structures, or other confidential data that could aid in more sophisticated exploitation attempts.
The vulnerability aligns with CWE-362, which specifically addresses race conditions in concurrent programming environments, and demonstrates how improper synchronization in kernel space can create exploitable conditions. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and system compromise through kernel-level flaws. The attack surface is primarily limited to local users who can execute processes on the affected system, but the potential for information disclosure makes it particularly concerning for environments where multiple users share the same system resources. The race condition affects the fundamental session management capabilities of the Linux kernel, making it a critical vulnerability that requires immediate attention and patching.
Mitigation strategies for CVE-2005-0178 involve upgrading to Linux kernel versions 2.6.8.1 or later where the race condition has been properly addressed through enhanced synchronization mechanisms. System administrators should implement comprehensive patch management procedures to ensure all affected systems receive the necessary kernel updates. Additionally, monitoring for unusual system crashes or kernel oops messages can help identify potential exploitation attempts. Organizations should also consider implementing additional security controls such as process isolation, restricted user privileges, and regular security audits to minimize the attack surface and reduce the potential impact of such vulnerabilities in their environments.