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