CHAINLINECHAINLINE

CHAINLINE is a Python webshell backdoor that is embedded in a Ivanti Connect Secure Python package that enables arbitrary command execution./nCHAINLINE was identified in the CAV Python package in the following path: /home/venv3/lib/python3.6/site-packages/cav-0.1-py3.6.egg/cav/api/resources/health.py. This is the same Python package modified to support the WIREFIRE web shell./nUnlike WIREFIRE, which modifies an existing file, CHAINLINE creates a new file called health.py, which is not a legitimate filename in the CAV Python package. The existence of this filename or an associated compiled Python cache file may indicate the presence of CHAINLINE./nUNC5221 registered a new API resource path to support the access of CHAINLINE at the REST endpoint /api/v1/cav/client/health. This was accomplished by importing the maliciously created Health API resource and then calling the add_resource() class method on the FLASK-RESTful Api object within /home/venv3/lib/python3.6/site-packages/cav-0.1-py3.6.egg/cav/api/__init__.py.