Slow loris HTTP attack

Slowloris is the name of a perl-based HTTP client that can be used as a denial of service against Apache-based HTTP servers.

Slowloris tries to keep many connections to the target web server open and hold them open as long as possible.

It accomplishes this by opening connections to the target web server and sending a partial request. Periodically, it will send subsequent HTTP headers, adding to—but never completing—the request. Affected servers will keep these connections open, filling their maximum concurrent connection pool, eventually denying additional connection attempts from clients.

Reference:- http://en.wikipedia.org/wiki/Slowloris

How to mitigate Slowloris Attack. :- http://www.funtoo.org/Slowloris_DOS_Mitigation_Guide