CVE-2020-5196

Cerberus FTP Server Enterprise Edition prior to versions 11.0.3 and 10.0.18 allows an authenticated attacker to create files, display hidden files, list directories, and list files without the permission to zip and download (or unzip and upload) files. There are multiple ways to bypass certain permissions by utilizing the zip and unzip features. As a result, users without permission can see files, folders, and hidden files, and can create directories without permission.

Weakness

During installation, installed file permissions are set to allow anyone to modify those files.

Affected Software

Potential Mitigations

• Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
• Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/1.html
• https://cwe.mitre.org/data/definitions/127.html
• https://cwe.mitre.org/data/definitions/81.html

References

• https://support.cerberusftp.com/hc/en-us/community/topics/360000164199-Announcements
• https://www.cerberusftp.com/zip-unzip-permission-bypass-vulnerability-fixed-in-cerberus-ftp-server-versions-11-0-3-and-10-0-18/
• https://www.doyler.net/security-not-included/cerberus-ftp-vulnerabilities