Elcom CommunityManager.NET Auth Bypass Vulnerability - Security Advisory - SOS-10-004
Release Date.                  20-Dec-2010
Last Update.                   -
Vendor Notification Date.      22-Jan-2010
Product.                       Elcom Technology's
                               CommunityManager.NET
Platform.                      IIS with ASP.NET
Affected versions.             v6.7 verified and 
                               possibly others.
Severity Rating.               High
Impact.                        Application "System" user access
Attack Vector.                 Remote without authentication
Solution Status.               Vendor patch
CVE reference.                 Not yet assigned

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.

About us.
Sense of Security is a leading provider of information
security and risk management solutions. Our team has expert
skills in assessment and assurance, strategy and architecture,
and deployment through to ongoing management. We are
Australia's premier application penetration testing firm and
trusted IT security advisor to many of the countries largest
organisations.

Sense of Security Pty Ltd 
Level 8, 66 King St
Sydney NSW 2000
AUSTRALIA

T: +61 (0)2 9290 4444
F: +61 (0)2 9290 4455
W: http://www.senseofsecurity.com.au/consulting/penetration-testing
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The latest version of this advisory can be found at:
http://www.senseofsecurity.com.au/advisories/SOS-10-004.pdf