CVE-2007-5191 in loop-aes-utils
Summary
by MITRE
mount and umount in util-linux and loop-aes-utils call the setuid and setgid functions in the wrong order and do not check the return values, which might allow attackers to gain privileges via helpers such as mount.nfs.
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Analysis
by VulDB Data Team • 06/03/2025
The vulnerability described in CVE-2007-5191 represents a critical privilege escalation flaw affecting the mount and umount utilities within the util-linux and loop-aes-utils packages. This issue stems from improper handling of setuid and setgid function calls during the privilege transition process, creating a window where malicious actors can exploit the system's privilege management mechanisms. The flaw specifically manifests when these utilities execute helper programs such as mount.nfs, which themselves may be vulnerable to manipulation by unprivileged users. The vulnerability operates at the core of Unix-like operating system security models where proper privilege management is essential for maintaining system integrity and preventing unauthorized access to protected resources.
The technical implementation of this vulnerability involves a fundamental error in the order of system calls within the mount and umount executables. When these utilities attempt to change user and group identifiers to execute helper programs, they call setuid and setgid functions in an incorrect sequence, which can result in the effective user ID not being properly set before the helper program executes. This misordering creates a race condition where the program executes with elevated privileges but without proper privilege validation. The absence of return value checking for these system calls compounds the issue, as errors in privilege elevation are silently ignored, allowing the system to continue execution in a compromised state where the attacker may have gained unauthorized access to root privileges or other elevated permissions.
The operational impact of this vulnerability extends beyond simple privilege escalation, affecting the fundamental security posture of systems running affected versions of util-linux and loop-aes-utils. Attackers exploiting this vulnerability can potentially gain root access to systems, allowing them to modify critical system files, install malicious software, or establish persistent backdoors. The vulnerability is particularly dangerous because it leverages legitimate system utilities that are typically trusted and frequently executed, making detection more difficult for security monitoring systems. The exploitation chain typically involves an attacker first gaining access to a user account, then executing mount or umount commands with specific parameters that trigger the privilege escalation, ultimately resulting in unauthorized system control.
Mitigation strategies for this vulnerability require immediate patching of affected systems with updated versions of util-linux and loop-aes-utils that correct the setuid/setgid function call ordering and implement proper return value checking. System administrators should also consider implementing additional security controls such as restricting execution permissions on mount and umount utilities, monitoring for unusual privilege escalation attempts, and ensuring that helper programs like mount.nfs are properly secured. The vulnerability aligns with CWE-276, which addresses improper privilege management, and corresponds to techniques in the MITRE ATT&CK framework under privilege escalation tactics, specifically focusing on the execution of privileged commands through compromised system utilities. Organizations should also conduct comprehensive vulnerability assessments to identify any systems that may be running older versions of these utilities and implement automated patch management processes to prevent similar issues from arising in the future.