[securitylab.ru & security.nnov] Kerio Winroute Firewall Xroxy problem
Application: Kerio Winroute Firewall 5.10
Vendor: Kerio Technologies Inc.
Vendor Site: http://www.kerio.com
Remote: Yes
Exploitable: Yes
Risk level: Critical (if proxy requires authentication)
Authors: Alexander Antipov & 3APA3A (aka Pig Killer)
Authors Sites: http://www.securitylab.ru http://www.security.nnov.ru
Intro:
Winroute is most popular SOHO software firewall/router/Proxy solution
for Windows platform.
Vulnerability:
During troubleshooting of Winroute a security related problem was
discovered allowing remote website to obtain cleartext credentials
(username:password) of WinRoute user.
Details:
WinRoute has extremely weak functionality as a proxy server. It doesn't
rebuild request sent by browser. Instead, it only changes Proxy- related
header by substituting fist character to X (So, for example,
Proxy-Connection header becomes Xroxy-Connection: in outgoing request).
It leads to few troubles. First, it leaks HTTP established connections.
Every file (for exmple .gif, html, jpg) from web server requires
separate connection resulting in performance degradation. But, of cause,
security related problem is in handling Proxy-Authorization: header sent
by browser. Browser sends this header with every request in a case proxy
server requires authentication. This header contains base64-encoded
username and password of proxy user in cleartext (NTLM and Kerberos
probably is not supported by WinRoute). If WinRoute uses windows
authentication this credentials contain domain account information.
As a result, any webserver visited by WinRoute user can track his proxy
username and password by Xroxy-Authorization: header (X because first
character is changed). For example
Xroxy-Authorization: Basic dGVzdDp0ZXN0aW5n
(test:testing).
Workaround:
Disable proxy authentication
Greets:
to Ink-Visitor who still awaiting for his document from Pig.
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