source: https://www.securityfocus.com/bid/2736/info

Microsoft IIS 5.0 is vulnerable to a denial of service attack.

A flaw in the WebDav extensions allow a remote attacker to carry out a DoS by repeatedly requesting nonexistent files via the HTTP LOCK method.

This leads to a complete consumption of memory resources, eventually crashing the host and requiring a restart.

LOCK /aaaaaaaaaaaaaaaaaaaaaaaaaa.htw HTTP/1.0

One way is to combine the attack with asp executions, eg.

GET /iisstart.asp?uc=a HTTP/1.0