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ISS Security Brief: Microsoft ASN.1 Integer Manipulation Vulnerabilities



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Internet Security Systems Security Brief
February 11, 2004

Microsoft ASN.1 Integer Manipulation Vulnerabilities

Synopsis:

Microsoft has release Security Bulletin MS04-007 to address vulnerabilities 
in the ASN.1 parsing component of the Windows Operating Systems. This 
component is used by several applications for transmission of data across 
the network. Some examples of applications which make use of ASN.1 include 
Internet Explorer and IIS for certificate parsing, NTLMv2 authentication, 
Kerberos authentication, ISAKMP, LDAP and Exchange.

Impact:

The vulnerability could be exploited by remote attackers to cause a Denial 
of Service (DoS) or potentially gain access to a vulnerable machine with 
the privileges of the services being exploited. This vulnerability may be 
exploited in many default configurations if vulnerable services are remotely 
accessible.

There are currently no known exploits in the wild for this issue. Due to 
the nature of this vulnerability, reliable and successful remote 
exploitation is considered difficult.

Known Affected Products:

Microsoft Windows NT4, 2000, XP and 2003 when used with one of the 
following applications:

- - NTLMv2 authentication
- - Internet Explorer
- - Outlook
- - IIS 4.0, 5.0, 5.1 and 6.0 with client certificate parsing enabled
- - ISAKMP/IPSec 
- - Exchange 5.x, 2000, 2003
- - LDAP
- - Kerberos

For complete ISS X-Force Security Alert, please visit: 
http://xforce.iss.net/xforce/alerts/id/164


______ 


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