Error message discloses existence of file in write-only share (NC-SA-2017-003)
5th February 2017
Risk level: Low
CVSS v3 Base Score: 3.7 (AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:L)
CWE: Information Exposure Through an Error Message (CWE-209)
HackerOne report: 174524
Description
Due to an error in the application logic an adversary with access to a write-only share may enumerate the names of existing files and subfolders by comparing the exception messages.
Affected Software
- Nextcloud Server < 10.0.2 (CVE-2017-0885)
- Nextcloud Server < 9.0.55 (CVE-2017-0885)
Action Taken
The error in the application logic has been addressed.
Resolution
It is recommended that all instances are upgraded to Nextcloud 9.0.55 or 10.0.2.
Acknowledgements
The Nextcloud team thanks the following people for their research and responsible disclosure of the above advisory:
This advisory is licensed CC BY-SA 4.0.