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TITLE:
Microsoft Windows RPC Mutual Authentication Vulnerability

SECUNIA ADVISORY ID:
SA20637

VERIFY ADVISORY:
http://secunia.com/advisories/20637/

CRITICAL:
Moderately critical

IMPACT:
Spoofing

WHERE:
>From local network

OPERATING SYSTEM:
Microsoft Windows 2000 Advanced Server
http://secunia.com/product/21/
Microsoft Windows 2000 Datacenter Server
http://secunia.com/product/1177/
Microsoft Windows 2000 Professional
http://secunia.com/product/1/
Microsoft Windows 2000 Server
http://secunia.com/product/20/

DESCRIPTION:
A vulnerability has been reported in Microsoft Windows, which can be
exploited by malicious people to spoof a valid RPC server.

The vulnerability is caused due to an error within the handling of
RPC mutual authentication. This can be exploited to cause custom RPC
clients to incorrectly validate the identity of the RPC server, which
potentially allows a malicious RPC server to impersonate a valid
service.

Successful exploitation requires that RPC clients use SSL with mutual
authentication option enabled and that a user e.g. is tricked into
connecting to a malicious RPC server.

SOLUTION:
Apply patch.

Microsoft Windows 2000 SP4:
http://www.microsoft.com/downloads/details.aspx?FamilyId=5089d956-7d8d-4241-9ca2-107ce4f8c093

PROVIDED AND/OR DISCOVERED BY:
The vendor credits Michael Colson of Symantec.

ORIGINAL ADVISORY:
MS06-031 (KB917736):
http://www.microsoft.com/technet/security/Bulletin/MS06-031.mspx

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About:
This Advisory was delivered by Secunia as a free service to help
everybody keeping their systems up to date against the latest
vulnerabilities.

Subscribe:
http://secunia.com/secunia_security_advisories/

Definitions: (Criticality, Where etc.)
http://secunia.com/about_secunia_advisories/


Please Note:
Secunia recommends that you verify all advisories you receive by
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Secunia NEVER sends attached files with advisories.
Secunia does not advise people to install third party patches, only
use those supplied by the vendor.

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