SB2021080401 - Multiple vulnerabilities in ownCloud Server

Description

This security bulletin contains information about 4 secuirty vulnerabilities.

1) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2021-35946)

The vulnerability allows a remote authenticated attacker to escalate privileges on the system.

The vulnerability exists due to the federated share recipient can increase permissions, which leads to security restrictions bypass and privilege escalation.

2) Information disclosure (CVE-ID: CVE-2021-35947)

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to excessive data output by the application. A remote authenticated attacker can display the internal path and username of the share owner.

3) Session Fixation (CVE-ID: CVE-2021-35948)

The vulnerability allows a local user to compromise the target system.

The vulnerability exists due to the session cookies are not reset after authenticating for public linkse. A remote attacker can obtain sensitive information on the system.

4) Improper Protection of Alternate Path (CVE-ID: CVE-2021-35949)

The vulnerability allows a remote attacker to compromise the target system.

The vulnerabiity exists due to the permission check for a file drop can be circumvented by using the shareinfo API. A remote authenticated attacker can see the files in the filedrop.

Remediation

Install update from vendor's website.

References

• https://owncloud.com/security-advisories/cve-2021-35946/
• https://owncloud.com/security-advisories/cve-2021-35947/
• https://owncloud.com/security-advisories/cve-2021-35948/
• https://owncloud.com/security-advisories/cve-2021-35949/