Linux Kernel TIOCSCTTY Race Condition Leads to Privilege Escalation

Executive Summary

This is a race condition vulnerability in the TIOCSCTTY ioctl handler in FreeBSD. The handler drops the tty lock to acquire the process tree lock but fails to revalidate the terminal state after reacquiring the tty lock. This allows a malicious local user to link a terminal that is being destroyed to their process session, enabling privilege escalation.

Useful 0 Not Useful 0

Detection Guidance

This vulnerability is a local privilege escalation issue in FreeBSD related to the TIOCSCTTY ioctl handler. Detection requires checking for unusual process behavior or terminal session manipulation. No specific commands are provided in the context, but monitoring for unexpected privilege changes or terminal session modifications may help identify exploitation attempts.

Useful 0 Not Useful 0

Impact Analysis

An unprivileged local user can exploit this flaw to gain elevated privileges on the system. This could allow them to execute arbitrary code with higher permissions, potentially leading to full system compromise or unauthorized access to sensitive data.

Useful 0 Not Useful 0

Mitigation Strategies

Apply the latest FreeBSD security patches or updates that address this issue. Since this is a local privilege escalation, restrict unprivileged user access to sensitive operations and monitor for suspicious activity. No specific mitigation commands are provided in the context.

Useful 0 Not Useful 0