Security Advisory – Elcom Technology’s CommunityManager.NET Auth Bypass Vulnerability

Sense of Security – Security Advisory – SOS-10-004

Details.

The web application uses cookie parameters passed via HTTP requests to identify which user is logged in. Authentication routines can be bypassed by simply appending the below POC string to a cookie which already contains a valid ASP.NET session ID. The value given to the various cookie parameters indicates the specific user ID for the application user the attacker wishes to impersonate.

Proof of Concept.

To exploit this vulnerability, simply browse to the software to automatically create a valid ASP.NET session ID. Once obtained, add the following to the cookie parameter:

; CMLogUserwww2=21; OnlineLearnUserwww2=21

Note that the ID value of “21” in the above instance indicates that the user with the user ID of “21” will be impersonated. If this user ID is not linked to a user account, access will not be obtained. Some enumeration or educated guessing may be required.

Solution.

Sense of Security has been advised that Elcom Technology has patched all versions of CommunityManager.NET and notified all clients.

Discovered by.

Sense of Security Labs.