IIS 4.0 Denial of Service Vulnerability

The IIS 4.0 web server is a widely used software for hosting websites and web applications. This vulnerability allows remote attackers to cause a denial of service by sending a malformed request for files with specific extensions, such as .HTR, .IDC, or .STM.

You're affected if you use Microsoft Internet Information Services (IIS) version 4.0. Check with: dir /b /s %windir%\system32\inetsrv\httpd.dll to verify the presence of the httpd.dll file.

Note: This vulnerability is specific to IIS 4.0 and not related to other Microsoft products or services.

To fix this vulnerability, you can upgrade to a newer version of IIS that includes a patch for this issue. You can download the update from the Microsoft Support website:

• Windows Server 2003: https://support.microsoft.com/en-us/kb/234905
• Windows XP: https://support.microsoft.com/en-us/kb/234905

Immediate mitigations:

• Restrict network access to your IIS 4.0 server (firewall it from the public internet)
• Monitor for unusual system activity and potential denial of service attacks

• support.microsoft.com
• www.ciac.org
• www.eeye.com
• docs.microsoft.com
• oval.cisecurity.org
• support.microsoft.com
• www.ciac.org
• www.eeye.com
• docs.microsoft.com
• oval.cisecurity.org