CVE-2002-0767 in simpleinit
Summary
by MITRE
simpleinit on Linux systems does not close a read/write FIFO file descriptor before creating a child process, which allows the child process to cause simpleinit to execute arbitrary programs with root privileges.
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Analysis
by VulDB Data Team • 11/30/2024
The vulnerability identified as CVE-2002-0767 affects the simpleinit utility commonly found on Linux systems, representing a critical privilege escalation flaw that has significant implications for system security. This issue stems from improper file descriptor handling within the initialization process, where the simpleinit daemon fails to properly close a read/write FIFO file descriptor before spawning child processes. The flaw exists in the fundamental process management mechanism that governs how system services are initialized and maintained during boot cycles. When simpleinit creates child processes to handle various system tasks, it inherits file descriptors from its parent process, including the problematic FIFO descriptor that should have been closed. This inheritance allows malicious actors to manipulate the file descriptor state in ways that can be exploited to gain elevated privileges.
The technical exploitation of this vulnerability occurs through a specific race condition and file descriptor inheritance mechanism that violates standard security practices for process initialization. CWE-362 categorizes this as a race condition vulnerability where the timing of file descriptor closure and process creation creates an exploitable window. The flaw specifically relates to CWE-367, which addresses the execution of arbitrary code due to improper handling of file descriptors in privileged contexts. When an attacker can manipulate the FIFO file descriptor that remains open in the child process, they can potentially redirect program execution to arbitrary binaries with root privileges. The exploitation process typically involves creating a malicious FIFO file descriptor that, when inherited by the child process, triggers the execution of attacker-controlled programs. This represents a fundamental breakdown in the principle of least privilege and proper privilege separation during system initialization.
The operational impact of CVE-2002-0767 is severe and far-reaching, as it provides a direct path to root compromise on affected systems. Systems running vulnerable versions of simpleinit become immediately susceptible to privilege escalation attacks that can result in complete system takeover. The vulnerability affects systems that rely on simpleinit as their primary init system, which includes many embedded systems, older Linux distributions, and certain specialized appliances. Once exploited, attackers can execute arbitrary code with the highest system privileges, potentially leading to data exfiltration, system persistence, network reconnaissance, or complete compromise of the affected infrastructure. The attack vector is particularly concerning because it operates at the system initialization level, making it difficult to detect and prevent through traditional runtime security measures. This vulnerability essentially allows attackers to bypass normal authentication and authorization mechanisms by exploiting the privileged context in which simpleinit operates.
Mitigation strategies for this vulnerability focus on both immediate remediation and long-term architectural improvements to system security. The primary fix involves updating to patched versions of simpleinit or switching to more secure initialization systems such as systemd or sysvinit with proper file descriptor handling. Organizations should implement comprehensive patch management procedures to ensure all systems running vulnerable versions are updated promptly. Additionally, system administrators should consider implementing runtime protections such as file descriptor sandboxing and privilege separation mechanisms that prevent inheritance of unnecessary file descriptors. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically noting how process initialization flaws can be exploited to gain system-level access. Security monitoring should include detection of unusual file descriptor inheritance patterns and unexpected process creation events during system boot cycles. Regular security audits should verify that initialization processes properly close all unnecessary file descriptors and implement proper privilege separation to prevent similar vulnerabilities from emerging in other system components.