GEN:SID 1:1023
Message WEB-IIS msadcs.dll access
Summary This event is generated when an attempt is made to access the msadcs.dll file, which provides an interface to Remote Data Services (RDS).
Impact Information gathering or remote access. This attack may allow disclosure of file contents or may allow remote access to the vulnerable server.
Detailed Information Microsoft Data Access Components (MDAC) provides web and database integration.  The RDS component of MDAC enables remote web access to database services through the Internet Information Server (IIS).  A vulnerability exists in the DataFactory component of RDS that may permit unauthenticated users to query databases.  Depending on other software installed, it may be possible to execute arbitrary commands on IIS.
Affected Systems IIS 3.0, 4.0 servers
Attack Scenarios An attacker can exploit the vulnerability to get access to remote databases or, under certain software configurations, get access to the remote IIS server to run arbitrary commands.
Ease of Attack Simple.  Exploit code is freely available.
Corrective Action Follow the configuration changes in the referenced Microsoft link.

Upgrade to a more current version of IIS.
Additional References CVE
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-1999-1011

Bugtraq.
http://www.securityfocus.com/bid/529

Microsoft
http://www.microsoft.com/technet/security/bulletin/ms99-025.asp

Rule References bugtraq: 529
cve: 1999-1011
nessus: 10357