ZDI-07-055: Microsoft Windows DCERPC Authentication Denial of Service
            Vulnerability
http://www.zerodayinitiative.com/advisories/ZDI-07-055.html
October 10, 2007

-- CVE ID:
CVE-2007-2228

-- Affected Vendor:
Microsoft

-- Affected Products:
Windows 2000 SP4
Windows XP SP2
Windows 2003 SP1
Windows Vista

-- TippingPoint(TM) IPS Customer Protection:
TippingPoint IPS customers have been protected against this
vulnerability since October  9, 2007 by Digital Vaccine protection
filter ID 5657. For further product information on the TippingPoint IPS:

    http://www.tippingpoint.com 

-- Vulnerability Details:
This vulnerability allows remote attackers to crash systems with
vulnerable installations of the Microsoft Windows operating system.
Authentication is not required to exploit this vulnerability.

The specific flaw exists within the RPC runtime library rpcrt4.dll
during the parsing of RPC-level authentication messages. When parsing
packets with the authentication type of NTLMSSP and the authentication
level of PACKET, an invalid memory dereference can occur if the
verification trailer signature is initialized to 0 as opposed to the
standard NTLM signature. Successful exploitation crashes the RPC
service and subsequently the entire operating system.

-- Vendor Response:
Microsoft has issued an update to correct this vulnerability. More
details can be found at:

    http://www.microsoft.com/technet/security/bulletin/ms07-058.mspx

-- Disclosure Timeline:
2007.02.05 - Vulnerability reported to vendor
2007.10.09 - Digital Vaccine released to TippingPoint customers
2007.10.10 - Coordinated public release of advisory

-- Credit:
This vulnerability was discovered by Tenable Network Security.

-- About the Zero Day Initiative (ZDI):
Established by TippingPoint, a division of 3Com, The Zero Day Initiative
(ZDI) represents a best-of-breed model for rewarding security
researchers for responsibly disclosing discovered vulnerabilities.

Researchers interested in getting paid for their security research
through the ZDI can find more information and sign-up at:

    http://www.zerodayinitiative.com

The ZDI is unique in how the acquired vulnerability information is used.
3Com does not re-sell the vulnerability details or any exploit code.
Instead, upon notifying the affected product vendor, 3Com provides its
customers with zero day protection through its intrusion prevention
technology. Explicit details regarding the specifics of the
vulnerability are not exposed to any parties until an official vendor
patch is publicly available. Furthermore, with the altruistic aim of
helping to secure a broader user base, 3Com provides this vulnerability
information confidentially to security vendors (including competitors)
who have a vulnerability protection or mitigation product.


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