Microsoft ISA Server Web Proxy denial of service
| isa-web-proxy-dos (6383) |  Medium Risk |
Description:
Microsoft Internet Security and Acceleration (ISA) Server is vulnerable to a denial of service attack against the Web Proxy service. In versions of ISA with the Web Publishing feature enabled, a remote attacker can send an unusually long HTTP request to the Web Proxy service on port 80 to cause the service to fail. This results in preventing all incoming and outgoing Web traffic from passing through the firewall. The Web Proxy service must be restarted in order to regain normal functionality.
Platforms Affected:
- Microsoft, ISA Server 2000
Remedy:
Apply the patch for this vulnerability, as listed in Microsoft Security Bulletin MS01-045. See References.
Note: Microsoft originally provided a patch for this vulnerability in MS01-021, but it was superseded by the patch released with MS01-045.
Consequences:
Denial of Service
References:
- CIAC Information Bulletin L-073, Microsoft ISA Web Proxy Service Denial of Service at http://www.ciac.org/ciac/bulletins/l-073.shtml.
- Microsoft Security Bulletin MS01-021, Web Request Can Cause Access Violation in ISA Server Web Proxy Service at http://www.microsoft.com/technet/security/bulletin/ms01-021.mspx.
- Microsoft Security Bulletin MS01-045, ISA Server H.323 Gatekeeper Service Contains Memory Leak at http://www.microsoft.com/technet/security/bulletin/MS01-045.mspx Note: Microsoft originally provided a patch for this vulnerability in MS01-021, but it was superceded by the patch released with MS01-045..
- SecureXpert Labs Advisory SX-20010320-2, Denial of Service in Microsoft ISA server v1.0 at http://archives.neohapsis.com/archives/bugtraq/2001-04/0249.html.
- SecureXpert Labs Advisory SX-20010320-2b, Followup re. Microsoft ISA Server Denial of Service at http://archives.neohapsis.com/archives/bugtraq/2001-04/0293.html.
- BID-2600: Microsoft ISA Server Web Proxy DoS Vulnerability
- CVE-2001-0239: Microsoft Internet Security and Acceleration (ISA) Server 2000 Web Proxy allows remote attackers to cause a denial of service via a long web request with a specific type.
Reported:
Apr 16, 2001
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