major_rls51.txt

`[MajorSecurity Advisory #51]Virtual Hosting Control System - Session fixation Issue  
  
Details  
=======  
Product: Virtual Hosting Control System  
Affected version: 2.4.7.1 and prior  
Remote-Exploit: yes  
Vendor-URL: http://www.vhcs.net  
Vendor-Status: informed  
Advisory-Status: published  
  
Credits  
============  
Discovered by: David Vieira-Kurz  
http://www.majorsecurity.de  
  
Original Advisory:  
============  
http://www.majorsecurity.de/index_2.php?major_rls=major_rls51  
  
Introduction  
============  
"VHCS is a Professional Control Panel Software for shared, reseller, virtual and dedicated server management." - from vhcs.net  
  
More Details  
============  
1. Session fixation:  
The "PHPSESSID" parameter can be set to a malicious and arbitrary value.  
  
1.1 Description:  
In a session fixation attack, the attacker fixes the user's session ID before the user even logs into the target server.  
After a user's session ID has been fixed, the attacker will wait for them to login.  
Once the user does so, the attacker uses the predefined session ID value to assume their online identity.  
  
PoC:  
============  
http://localhost/vhcs2-2.4.7.1/gui/?PHPSESSID=15031988  
  
Workaround:  
============  
1. Do not accept session identifiers from GET / POST variables.  
  
2.Regenerate SID on each request.  
  
3. Accept only server generated SID:  
One way to improve security is to not accept session identifiers not generated by server.  
  
if ( ! isset( $_SESSION['SERVER_GENERATED_SID'] ) ) {  
session_destroy(); // destroy all data in session  
}  
session_regenerate_id(); // generate a new session identifier  
$_SESSION['SERVER_GENERATED_SID'] = true;  
  
  
History/Timeline  
================  
18.07.2007 discovery of the vulnerability  
20.07.2007 contacted the vendor  
20.07.2007 hotfix sent to the vendor   
21.07.2007 advisory is written  
21.07.2007 advisory released  
  
  
MajorSecurity  
=======  
MajorSecurity is a non-profit German penetration testing and security research project  
which consists of only one person at the present time.  
http://www.majorsecurity.de/  
`