Multiple cross-site request forgery (CSRF) vulnerabilities in ownCloud 4.5.x before 4.5.7 allow remote attackers to hijack the authentication of users for requests that (1) change the default view via the v parameter to apps/calendar/ajax/changeview.php, mount arbitrary (2) Google Drive or (3) Dropbox folders via vectors related to addRootCertificate.php, dropbox.php and google.php in apps/files_external/ajax/, or (4) change the authentication server URL via unspecified vectors to apps/user_webdavauth/settings.php.
Weakness
The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.
Affected Software
| Name |
Vendor |
Start Version |
End Version |
| Owncloud |
Owncloud |
4.5.0 (including) |
4.5.0 (including) |
| Owncloud |
Owncloud |
4.5.1 (including) |
4.5.1 (including) |
| Owncloud |
Owncloud |
4.5.2 (including) |
4.5.2 (including) |
| Owncloud |
Owncloud |
4.5.3 (including) |
4.5.3 (including) |
| Owncloud |
Owncloud |
4.5.4 (including) |
4.5.4 (including) |
| Owncloud |
Owncloud |
4.5.5 (including) |
4.5.5 (including) |
| Owncloud |
Owncloud |
4.5.6 (including) |
4.5.6 (including) |
| Owncloud |
Ubuntu |
upstream |
* |
Potential Mitigations
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- For example, use anti-CSRF packages such as the OWASP CSRFGuard. [REF-330]
- Another example is the ESAPI Session Management control, which includes a component for CSRF. [REF-45]
- Use the “double-submitted cookie” method as described by Felten and Zeller:
- When a user visits a site, the site should generate a pseudorandom value and set it as a cookie on the user’s machine. The site should require every form submission to include this value as a form value and also as a cookie value. When a POST request is sent to the site, the request should only be considered valid if the form value and the cookie value are the same.
- Because of the same-origin policy, an attacker cannot read or modify the value stored in the cookie. To successfully submit a form on behalf of the user, the attacker would have to correctly guess the pseudorandom value. If the pseudorandom value is cryptographically strong, this will be prohibitively difficult.
- This technique requires Javascript, so it may not work for browsers that have Javascript disabled. [REF-331]
References