mirror of https://github.com/MISP/misp-modules
123 lines
4.2 KiB
Python
123 lines
4.2 KiB
Python
import base64
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import io
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import logging
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import sys
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import zipfile
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import clamd
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from . import check_input_attribute, standard_error_message
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from typing import Optional
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from pymisp import MISPEvent, MISPObject
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log = logging.getLogger("clamav")
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log.setLevel(logging.DEBUG)
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sh = logging.StreamHandler(sys.stdout)
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sh.setLevel(logging.DEBUG)
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fmt = logging.Formatter(
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"%(asctime)s - %(name)s - %(levelname)s - %(message)s"
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)
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sh.setFormatter(fmt)
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log.addHandler(sh)
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moduleinfo = {
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"version": "0.1",
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"author": "Jakub Onderka",
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"description": "Submit file to ClamAV",
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"module-type": ["expansion"]
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}
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moduleconfig = ["connection"]
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mispattributes = {
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"input": ["attachment", "malware-sample"],
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"format": "misp_standard"
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}
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def create_response(original_attribute: dict, software: str, signature: Optional[str] = None) -> dict:
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misp_event = MISPEvent()
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if signature:
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misp_event.add_attribute(**original_attribute)
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av_signature_object = MISPObject("av-signature")
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av_signature_object.add_attribute("signature", signature)
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av_signature_object.add_attribute("software", software)
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av_signature_object.add_reference(original_attribute["uuid"], "belongs-to")
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misp_event.add_object(av_signature_object)
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event = misp_event.to_dict()
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results = {key: event[key] for key in ('Attribute', 'Object') if (key in event and event[key])}
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return {"results": results}
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def connect_to_clamav(connection_string: str) -> clamd.ClamdNetworkSocket:
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if connection_string.startswith("unix://"):
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return clamd.ClamdUnixSocket(connection_string.replace("unix://", ""))
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elif ":" in connection_string:
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host, port = connection_string.split(":")
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return clamd.ClamdNetworkSocket(host, int(port))
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else:
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raise Exception("ClamAV connection string is invalid. It must be unix socket path with 'unix://' prefix or IP:PORT.")
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def dict_handler(request: dict):
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connection_string: str = request["config"].get("connection")
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if not connection_string:
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return {"error": "No ClamAV connection string provided"}
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attribute = request.get("attribute")
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if not attribute:
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return {"error": "No attribute provided"}
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if not check_input_attribute(request['attribute']):
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return {'error': f'{standard_error_message}, which should contain at least a type, a value and an uuid.'}
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if attribute["type"] not in mispattributes["input"]:
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return {"error": "Invalid attribute type provided, expected 'malware-sample' or 'attachment'"}
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attribute_data = attribute.get("data")
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if not attribute_data:
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return {"error": "No attribute data provided"}
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try:
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clamav = connect_to_clamav(connection_string)
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software_version = clamav.version()
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except Exception:
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logging.exception("Could not connect to ClamAV")
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return {"error": "Could not connect to ClamAV"}
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try:
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data = base64.b64decode(attribute_data, validate=True)
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except Exception:
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logging.exception("Provided data is not valid base64 encoded string")
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return {"error": "Provided data is not valid base64 encoded string"}
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if attribute["type"] == "malware-sample":
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try:
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with zipfile.ZipFile(io.BytesIO(data)) as zipf:
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data = zipf.read(zipf.namelist()[0], pwd=b"infected")
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except Exception:
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logging.exception("Could not extract malware sample from ZIP file")
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return {"error": "Could not extract malware sample from ZIP file"}
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try:
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status, reason = clamav.instream(io.BytesIO(data))["stream"]
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except Exception:
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logging.exception("Could not send attribute data to ClamAV. Maybe file is too big?")
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return {"error": "Could not send attribute data to ClamAV. Maybe file is too big?"}
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if status == "ERROR":
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return {"error": "ClamAV returned error message: {}".format(reason)}
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elif status == "OK":
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return {"results": {}}
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elif status == "FOUND":
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return create_response(attribute, software_version, reason)
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else:
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return {"error": "ClamAV returned invalid status {}: {}".format(status, reason)}
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def introspection():
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return mispattributes
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def version():
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moduleinfo["config"] = moduleconfig
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return moduleinfo
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