In Reader View SameSite cookie protections are not checked on exiting. This allows for a payload to be triggered when Reader View is exited if loaded by a malicious site while Reader mode is active, bypassing CSRF protections. This vulnerability affects Firefox < 61.
Weakness
The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Ubuntu_linux | Canonical | 14.04 (including) | 14.04 (including) |
| Ubuntu_linux | Canonical | 16.04 (including) | 16.04 (including) |
| Ubuntu_linux | Canonical | 17.10 (including) | 17.10 (including) |
| Ubuntu_linux | Canonical | 18.04 (including) | 18.04 (including) |
| Firefox | Ubuntu | artful | * |
| Firefox | Ubuntu | bionic | * |
| Firefox | Ubuntu | devel | * |
| Firefox | Ubuntu | trusty | * |
| Firefox | Ubuntu | upstream | * |
| Firefox | Ubuntu | xenial | * |
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 [REF-1482].
- 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]
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/111.html
- https://cwe.mitre.org/data/definitions/462.html
- https://cwe.mitre.org/data/definitions/467.html
- https://cwe.mitre.org/data/definitions/62.html
References
- http://www.securitytracker.com/id/1041193
- https://bugzilla.mozilla.org/show_bug.cgi?id=1456652
- https://security.gentoo.org/glsa/201810-01
- https://usn.ubuntu.com/3705-1/
- https://www.mozilla.org/security/advisories/mfsa2018-15/
- http://www.securitytracker.com/id/1041193
- https://bugzilla.mozilla.org/show_bug.cgi?id=1456652
- https://security.gentoo.org/glsa/201810-01
- https://usn.ubuntu.com/3705-1/
- https://www.mozilla.org/security/advisories/mfsa2018-15/