CVE-2011-1182 in Linux
Summary
by MITRE
kernel/signal.c in the Linux kernel before 2.6.39 allows local users to spoof the uid and pid of a signal sender via a sigqueueinfo system call.
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Analysis
by VulDB Data Team • 12/29/2021
The vulnerability described in CVE-2011-1182 represents a critical privilege escalation flaw within the Linux kernel's signal handling mechanism. This vulnerability exists in the kernel/signal.c file and affects Linux kernel versions prior to 2.6.39, making it a significant concern for system administrators and security professionals managing legacy kernel environments. The flaw specifically targets the sigqueueinfo system call which is responsible for sending signals between processes, creating a pathway for local attackers to manipulate critical process identification information.
The technical implementation of this vulnerability stems from improper validation of signal sender identification within the kernel's signal delivery framework. When a local user executes a sigqueueinfo system call, the kernel fails to properly verify or sanitize the uid and pid fields of the signal structure. This allows an attacker to craft malicious signal data where the sender's user identifier and process identifier can be arbitrarily set to values different from the actual sender. The vulnerability operates at the kernel level, bypassing normal user-space process isolation mechanisms and creating a fundamental breach in the kernel's security model. This flaw is classified under CWE-284, which deals with improper access control, and specifically relates to insufficient privilege checks in kernel operations.
The operational impact of CVE-2011-1182 is substantial as it enables local privilege escalation attacks that can potentially allow an unprivileged user to impersonate other users or processes within the system. An attacker could exploit this vulnerability to send signals that appear to originate from processes with elevated privileges or different user contexts, thereby undermining the integrity of signal-based process communication and potentially enabling further attack vectors. The vulnerability is particularly dangerous because it operates silently within the kernel, making detection difficult and allowing attackers to establish persistent access patterns that could evade standard monitoring mechanisms.
Mitigation strategies for this vulnerability require immediate kernel version upgrades to 2.6.39 or later, as this represents the most effective and comprehensive solution. System administrators should prioritize patching affected systems and implementing proper kernel version controls to prevent exploitation. Additionally, organizations should consider implementing runtime monitoring solutions that can detect anomalous signal behavior patterns and establish process isolation measures to limit the potential impact of such vulnerabilities. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the T1068 - Exploitation for Privilege Escalation tactic, and demonstrates how kernel-level flaws can be leveraged to bypass traditional security controls. Organizations should also maintain comprehensive patch management processes and regularly audit their kernel versions to prevent similar vulnerabilities from remaining unaddressed in production environments.