Wednesday, December 12, 2007
discovered by mrhinkydink
PRODUCT: Websense Enterprise 6.3.1
EXPOSURE: Web Filtering Bypass
By spoofing the User-Agent header it is possible to bypass filtering and, to a lesser extent, monitoring in a Websense Enterprise 6.3.1 environment.
PROOF OF CONCEPT
The following was tested in an unpatched 6.3.1 system using the ISA Server integration product. It is assumed it will work with other integration products but this has not been tested. Other User Agents may also work.
I. Install FireFox 2.0.x
II. Obtain and install the User Agent Switcher browser plug-in by Chris Pederick
III. Add the following User Agents to the plug-in
User Agent : RealPlayer G2
Description: MSN Messenger
User Agent : MSMSGS
User Agent : StoneHttpAgent
IV. Change FireFox's User Agent to any one of the preceding values
V. Browse to a filtered Web site
VI. Content is allowed
Content browsed via this method will be recorded in the Websense database as being in the "Non-HTTP" category.
Websens Policy Bypass (obsolete)
Websense KnowledgeBase article #976
The vendor acknowledges this behavior in the aforementioned article.
Disable the protocols mentioned above.
Websense cleaned up this issue in database #92938
mrhinkydink is not to be confused with the blogger by the same name at www.dailykos.com
c. MMVII mrhinkydink