SB2017032811 - Improper Authorization in Nextcloud Server
Published: March 28, 2017 Updated: July 18, 2020
Security Bulletin ID
SB2017032811
Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Improper Authorization (CVE-ID: CVE-2016-9464)
The vulnerability allows a remote authenticated user to manipulate data.
Nextcloud Server before 9.0.54 and 10.0.0 suffers from an improper authorization check on removing shares. The Sharing Backend as implemented in Nextcloud does differentiate between shares to users and groups. In case of a received group share, users should be able to unshare the file to themselves but not to the whole group. The previous API implementation simply unshared the file to all users in the group.
Remediation
Install update from vendor's website.
References
- http://www.securityfocus.com/bid/97287
- https://github.com/nextcloud/server/commit/3387e5d00fcf6b2ea6b285a091e5743f545e7202
- https://github.com/nextcloud/server/commit/7289cb5ec0b812992ab0dfb889744b94bc0994f0
- https://github.com/nextcloud/server/commit/a5471b4a3e3f30e99e4de39c97c0c3b3c2f1618f
- https://github.com/nextcloud/server/commit/e2c4f4f9aa11bc92e8f2212cce73841b922187e8
- https://hackerone.com/reports/153905
- https://nextcloud.com/security/advisory/?id=nc-sa-2016-007