GEN:SID 1:2386
Message WEB-IIS NTLM ASN.1 vulnerability scan attempt
Summary This event is generated when an attempt is made to scan for a known
vulnerability in the Microsoft implementation of the ASN.1 Library using
Nessus.
Impact Intelligence gathering.
Detailed Information A buffer overflow condition in the Microsoft implementation of the ASN.1
Library. It may be possible for an attacker to exploit this condition by
sending specially crafted authentication packets to a host running a
vulnerable operating system.

When the taget system decodes the ASN.1 data, exploit code may be included
in the data that may be excuted on the host with system level privileges.
Alternatively, the malformed data may cause the service to become
unresponsive thus causing the DoS condition to occur.

This event indicates a possible attempt to enumerate vulnerable hosts using
Nessus.
Affected Systems Microsoft Windows NT
    Microsoft Windows NT Terminal Server Edition
    Microsoft Windows 2000
    Microsoft Windows XP
    Microsoft Windows 2003
Attack Scenarios  
Ease of Attack Simple. Exploit code exists.
Corrective Action Apply the appropriate vendor supplied patches.
Additional References  
Rule References nessus: 12055
nessus: 12052
bugtraq: 9635
cve: 2003-0818
bugtraq: 9633
nessus: 12065
url: www.microsoft.com/technet/security/bulletin/MS04-007.mspx