Description
acl before version 2.4.0 contains a time-of-check to time-of-use (TOCTOU) race condition vulnerability that allows local attackers to escalate privileges by replacing a pathname component with a symbolic link between an lstat() check and subsequent symlink-following operations such as stat(), chown(), chmod(), acl_get_file(), and acl_set_file(). Attackers who control a pathname component can redirect file access control list operations to arbitrary files when getfacl, setfacl, or chacl is invoked by a privileged process over an attacker-controlled path, resulting in local privilege escalation.
Problem types
Time-of-check Time-of-use (TOCTOU) Race Condition
Product status
Any version before 2.4.0
Credits
Andrew Tridgell
Andreas Gruenbacher
References
cgit.git.savannah.nongnu.org/...b34bdd9265936e17190b6d3f17d1
cgit.git.savannah.nongnu.org/...76612194f8a56c2314389adc74a5
www.vulncheck.com/...ink-traversal-via-getfacl-setfacl-chacl