[securitylab.ru & security.nnov] Kerio Winroute Firewall Xroxy problem

From: 3APA3A (3APA3A_at_SECURITY.NNOV.RU)
Date: 11/19/03

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    Date:         Wed, 19 Nov 2003 19:07:43 +0300
To: NTBUGTRAQ@LISTSERV.NTBUGTRAQ.COM

    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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