CVE-2019-15621 Explained : Impact and Mitigation
Learn about CVE-2019-15621, a privilege escalation vulnerability in Nextcloud Server version 16.0.1, allowing unauthorized users to reshare shared mount points with write permissions.
Nextcloud Server version 16.0.1 has a flaw that allows recipients of a shared mount point to reshare it with write permissions as a public link.
Understanding CVE-2019-15621
This CVE involves a privilege escalation vulnerability in Nextcloud Server version 16.0.1.
What is CVE-2019-15621?
CVE-2019-15621 is a vulnerability in Nextcloud Server 16.0.1 that enables users to reshare a shared mount point with write permissions as a public link.
The Impact of CVE-2019-15621
The vulnerability allows unauthorized users to escalate their privileges by resharing shared mount points with write permissions.
Technical Details of CVE-2019-15621
This section provides technical details about the vulnerability.
Vulnerability Description
Nextcloud Server version 16.0.1 improperly preserves permissions, enabling sharees to reshare with write permissions when sharing the mount point as a public link.
Affected Systems and Versions
- Product: Nextcloud Server
- Version: 16.0.2
Exploitation Mechanism
The flaw in maintaining permissions in Nextcloud Server 16.0.1 allows recipients of shared mount points to reshare them with write permissions as public links.
Mitigation and Prevention
Protect your systems from CVE-2019-15621 with the following steps:
Immediate Steps to Take
- Upgrade Nextcloud Server to a patched version.
- Restrict sharing permissions to trusted users.
Long-Term Security Practices
- Regularly update and patch Nextcloud Server to address security vulnerabilities.
- Educate users on secure sharing practices to prevent unauthorized access.
Patching and Updates
Ensure timely installation of security patches and updates to mitigate the risk of privilege escalation vulnerabilities.