Module: Msf::Exploit::Remote::HTTP::WebEnrollment

Includes:
CertRequest, LDAP::ActiveDirectory::AdCsOpts
Defined in:
lib/msf/core/exploit/remote/http/web_enrollment.rb

Overview

This module provides a way of interacting with the Microsoft AD/CS web enrollment portal

Instance Method Summary collapse

Methods included from LDAP::ActiveDirectory::AdCsOpts

#initialize, #validate

Methods included from CertRequest

#create_csr, #get_cert_msext_sid, #get_cert_msext_upn, #get_cert_policy_oids, #get_cert_san, #get_cert_san_dns, #get_cert_san_email, #get_cert_san_uri, #with_adcs_certificate_request

Instance Method Details

#add_cert_entry(connection_identity, cert_template) ⇒ Object 



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# File 'lib/msf/core/exploit/remote/http/web_enrollment.rb', line 30

def add_cert_entry(connection_identity, cert_template)
  if @issued_certs.key?(connection_identity)
    @issued_certs[connection_identity] << cert_template
  else
    @issued_certs[connection_identity] = [ cert_template ]
  end
end

#cert_issued?(connection_identity, cert_template) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/msf/core/exploit/remote/http/web_enrollment.rb', line 49

def cert_issued?(connection_identity, cert_template)
  !!@issued_certs[connection_identity]&.include?(cert_template)
end

#do_request_cert(http_client, opts, csr, attributes) ⇒ Object 



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# File 'lib/msf/core/exploit/remote/http/web_enrollment.rb', line 71

def do_request_cert(http_client, opts, csr, attributes)
  res = send_request_raw(
    {
      'client' => http_client,
      'method' => 'POST',
      'uri' => normalize_uri(datastore['TARGETURI'], 'certfnsh.asp'),
      'ctype' => 'application/x-www-form-urlencoded',
      'vars_post' => {
        'Mode' => 'newreq',
        'CertRequest' => Rex::Text.encode_base64(csr.to_der.to_s),
        'CertAttrib' => attributes.map { |k, v| "#{k}:#{v}" }.join("\n"),
        'TargetStoreFlags' => 0,
        'SaveCert' => 'yes',
        'ThumbPrint' => ''
      },
      'cgi' => true
    }
  )

  cert_template = opts[:cert_template]
  connection_identity = "#{opts[:domain]}\\#{opts[:username]}"

  if res.nil?
    print_bad('Certificate request failed, no response was received from the server')
    return nil
  end

  if res.code == 200 && res.body.include?('request was denied')
    print_bad("Certificate request denied using template #{cert_template} for #{connection_identity}")
    return nil
  end

  if res.code == 200 && res.body.include?('request failed')
    print_bad("Certificate request failed using template #{cert_template} for #{connection_identity}")
    return nil
  end
  if res.code == 401 && res.body.include?('invalid credentials')
    print_bad("Invalid Credential Error returned when using template #{cert_template} for #{connection_identity}")
    return nil
  end
  print_good("Certificate generated using template #{cert_template} for #{connection_identity}")
  add_cert_entry(connection_identity, cert_template)

  begin
    location_tag = res.body.match(/^.*location="(.*)"/)[1]
  rescue NoMethodError
    print_bad('Unable to locate location tag')
    return nil
  end

  location_uri = normalize_uri(target_uri, location_tag)
  vprint_status("Attempting to download the certificate from #{location_uri}")
  res = send_request_raw(
    {
      'client' => http_client,
      'method' => 'GET',
      'uri' => location_uri
    }
  )
  OpenSSL::X509::Certificate.new(res.body)
end

#get_cert_templates(http_client) ⇒ Object 



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# File 'lib/msf/core/exploit/remote/http/web_enrollment.rb', line 14

def get_cert_templates(http_client)
  print_status('Retrieving available template list, this may take a few minutes')
  res = send_request_raw(
    {
      'client' => http_client,
      'method' => 'GET',
      'uri' => normalize_uri(target_uri, 'certrqxt.asp')
    }
  )
  return nil unless res&.code == 200

  cert_templates = res.body.scan(/^.*Option Value="[E|O];(.*?);/).map(&:first)
  print_bad('Found no available certificate templates') if cert_templates.empty?
  cert_templates
end

#report_web_enrollment_service ⇒ Object 



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# File 'lib/msf/core/exploit/remote/http/web_enrollment.rb', line 133

def report_web_enrollment_service
  common = { host: rhost, port: rport, proto: 'tcp' }
  report_service({
    name: 'AD CS Web Enrollment',
    parents: {
      name: ssl ? 'https' : 'http',
      parents: {
        name: 'tcp'
      }.merge(common)
    }.merge(common)
  }.merge(common))
end

#retrieve_cert(http_client, connection_identity, cert_template) ⇒ Object 



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# File 'lib/msf/core/exploit/remote/http/web_enrollment.rb', line 53

def retrieve_cert(http_client, connection_identity, cert_template)
  opts = {
    username: connection_identity.split('\\').last,
    domain: connection_identity.split('\\').first,  # this is slightly inconsistent since it's the NETBIOS domain name not FQDN
    cert_template: cert_template,
  }

  with_adcs_certificate_request(opts) do |csr, attributes|
    if (certificate = do_request_cert(http_client, opts, csr, attributes))
      # Unlike with MS-ICPR we're not confident the target is the AD CS service we think it is until a
      # certificate is issued so wait and only report the service if it worked
      opts[:service] = report_web_enrollment_service
    end

    certificate
  end
end

#retrieve_certs(http_client, connection_identity, cert_templates) ⇒ Object 



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# File 'lib/msf/core/exploit/remote/http/web_enrollment.rb', line 38

def retrieve_certs(http_client, connection_identity, cert_templates)
  cert_templates.each do |cert_template|
    if cert_issued?(connection_identity, cert_template)
      print_status("Certificate already created for #{connection_identity} using #{cert_template}, skipping...")
      next
    end

    retrieve_cert(http_client, connection_identity, cert_template)
  end
end