Positive Technologies Security Advisory 2003-0307: DoS-attack in Kerio WinRoute Firewall

           Positive Technologies Security Advisory
                 http://www.ptsecurity.com


    Title: DoS-attack in Kerio WinRoute Firewall
     Date: March, 07 2003
 Severity: High

Application: Kerio WinRoute Firewall 5.0.1
Platform: Windows 95/98/ME/NT/2000/XP
Vendor Status: Notified, patched in version 5.0.2

I. DESCRIPTION

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Denial of Service condition exists in Kerio WinRoute Firewall's Web
administration interface which hand service with 100% CPU utilization.

Positive Technologies reports that single simple HTTP request to Kerio
Winroute Firewall Web administration interface (TCP/4080)

GET / HTTP/1.0
Authorization: Basic XXX

instead of correct one:

GET / HTTP/1.0
Host: server
Authorization: Basic XXX

causes 100% CPU utilization of attacked computer.

II. IMPACT

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Remote user can launch denial of service attack against web interface
(port TCP/4080). Single request causes 100% CPU utilization. As a result
more than 50% of future connection requests may be lost disturbing
normal functionality of the networking services.

III. SOLUTION

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Block TCP/4080 access or upgrade to Kerio WinRoute Firewall 5.0.2.

IV. VENDOR FIX/RESPONSE

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Vendor was notified on 10.03.2003.

V. CREDIT

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Positive Technologies is information security company especially focused on
protection of corporate networks from external attacks. The main trend of
PT’s activity is computer networks security audit and service. PT offers
wide range of services in the filed of information security: from network
architecture development or optimization to consulting and custom software
source-code examination.