CVE Vulnerabilities

CVE-2018-16854

Cross-Site Request Forgery (CSRF)

Published: Nov 26, 2018 | Modified: Oct 09, 2019
CVSS 3.x
8.8
HIGH
Source:
NVD
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS 2.x
6.8 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P
RedHat/V2
RedHat/V3
Ubuntu

A flaw was found in moodle versions 3.5 to 3.5.2, 3.4 to 3.4.5, 3.3 to 3.3.8, 3.1 to 3.1.14 and earlier. The login form is not protected by a token to prevent login cross-site request forgery. Fixed versions include 3.6, 3.5.3, 3.4.6, 3.3.9 and 3.1.15.

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
Moodle Moodle * 3.0.10
Moodle Moodle 3.1.0 *
Moodle Moodle 3.3.0 *
Moodle Moodle 3.4.0 *
Moodle Moodle 3.5.0 *

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