Rule--Sid:995--Summary:This event is generated when an attempt is made to request an HTTP-based password change.--Impact:Information gathering/remote access.  Error messages from failed password changes can indicate whether a given account exists on the server.  Successful password changes can allow remote access to the server. --Detailed Information:Microsoft Internet Information Services (IIS) Version 4 servers that were upgraded from IIS 2 or 3 have a legacy ism.dll file that allows web-based administration.  Upon sending a request to ism.dll, the user will be prompted for a userid and password.  An attacker can attempt to brute force guess a password, allowing remote access to the server.--Affected Systems:Microsoft IIS 4.0 servers upgraded from IIS 2.0 or 3.0--Attack Scenarios:An attacker can request password changes to discover existing accounts or brute force password changes.--Ease of Attack:Simple.--False Positives:None Known.--False Negatives:None Known.--Corrective Action:Upgrade to a more current version of ISS.Consider running the IIS Lockdown Tool to disable unnecessary functionality.--Contributors:Original rule writer unknownModified by Brian Caswell <bmc@sourcefire.com>Sourcefire Research TeamJudy Novak <judy.novak@sourcefire.com>--Additional References:CVEhttp://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-1999-1538Bugtraqhttp://www.securityfocus.com/bid/189--