CVE-2016-4445 in setroubleshoot
Summary
by MITRE
The fix_lookup_id function in sealert in setroubleshoot before 3.2.23 allows local users to execute arbitrary commands as root by triggering an SELinux denial with a crafted file name, related to executing external commands with the commands.getstatusoutput function.
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Analysis
by VulDB Data Team • 11/28/2022
The vulnerability identified as CVE-2016-4445 resides within the sealert component of the setroubleshoot package, specifically in the fix_lookup_id function that handles SELinux denial processing. This flaw represents a critical privilege escalation vulnerability that affects systems running setroubleshoot versions prior to 3.2.23. The vulnerability stems from improper input validation and unsafe command execution practices within the SELinux troubleshooting utility, which is designed to help administrators diagnose and resolve SELinux policy violations. The issue manifests when local users can manipulate the system by creating specially crafted filenames that trigger the vulnerable code path during SELinux denial processing.
The technical implementation of this vulnerability involves the exploitation of the commands.getstatusoutput function, which is used to execute external commands in a manner that does not properly sanitize user-supplied input. When a crafted filename is processed through the fix_lookup_id function, the malicious input gets passed directly to the command execution mechanism without adequate sanitization or validation. This creates a classic command injection scenario where attacker-controlled data can be interpreted as shell commands, allowing arbitrary code execution with root privileges. The vulnerability is particularly dangerous because it operates within the context of a system utility that is designed to handle security-related events, making it a prime target for privilege escalation attacks.
The operational impact of this vulnerability extends beyond simple command execution, as it enables attackers to gain full root access to affected systems. Local users who can trigger the specific conditions leading to the vulnerable function call can execute any command they choose with the highest system privileges. This capability allows for complete system compromise, enabling attackers to modify system files, install backdoors, exfiltrate data, or establish persistent access. The vulnerability affects systems where setroubleshoot is installed and actively used for SELinux policy troubleshooting, which includes many enterprise environments and security-conscious deployments. The attack vector is particularly concerning because it requires minimal privileges to exploit and can be triggered through normal system operations involving SELinux denial processing.
Security practitioners should implement immediate mitigations including updating to setroubleshoot version 3.2.23 or later, which contains the necessary patches to address the input validation issues. Additionally, system administrators should consider restricting access to the sealert utility and monitoring for unusual SELinux denial patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-78, which describes improper neutralization of special elements used in OS commands, and relates to ATT&CK technique T1068, which covers local privilege escalation through command injection. Organizations should also review their SELinux policies to minimize the attack surface and ensure that only authorized users have access to the affected functionality. The fix implemented in the patched version properly validates and sanitizes all input before processing, eliminating the command injection vulnerability that enabled the privilege escalation.