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.
https://exchange.xforce.ibmcloud.com/vulnerabilities/6383
https://euvd.enisa.europa.eu/vulnerability/EUVD-2001-0239
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2001/ms01-021
http://www.securityfocus.com/bid/2600
http://www.securityfocus.com/archive/1/179986
http://www.securityfocus.com/archive/1/177160