ownCloud alert 3 Critical Vulnerabilities Users to Data Breaches

The creators of the open-source file-sharing software ownCloud have alerted users about three serious security vulnerabilities. These flaws could allow attackers to access confidential information and make changes to files.

Brief description of the vulnerabilities is as follows:

Sensitive credentials and configuration in container deployments for graphapi versions 0.2.0 to 0.3.0 were exposed, leading to a security vulnerability with a CVSS score of 10.0.

WebDAV API authentication bypass through the use of pre-signed URLs affects core versions 10.6.0 to 10.13.0. This vulnerability has a CVSS score of 9.8.

Subdomain Validation Bypass impacting oauth2 prior to version 0.6.1 (CVSS score: 9.0)

“The first vulnerability involves the ‘graphapi’ app relying on a third-party library that exposes the PHP environment configuration details (phpinfo).”

“This information includes all the environment variables of the web server. In containerized deployments, these environment variables may include sensitive data such as the ownCloud admin password, mail server credentials, and license key.”

To fix the issue, ownCloud suggests removing the “owncloud/apps/graphapi/vendor/microsoft/microsoft-graph/tests/GetPhpInfo.php” file and disabling the ‘phpinfo’ function. Additionally, users are advised to update their ownCloud admin password, mail server and database credentials, and Object-Store/S3 access keys.

The second problem allows anyone to access, modify, or delete any file without needing authentication if they know the victim’s username and the victim hasn’t set up a signing-key, which is the default setting.

“Lastly, the third flaw relates to a case of improper access control that enables an attacker to redirect callbacks to a TLD controlled by the attacker without undergoing validation.”

Besides adding hardening measures to the validation code in the oauth2 app, ownCloud has suggested that users disable the “Allow Subdomains” option as a workaround.