5.3 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
7.1 High
AI Score
Confidence
High
0.001 Low
EPSS
Percentile
22.0%
Oppia is an online learning platform. When comparing a received CSRF token against the expected token, Oppia uses the string equality operator (==
), which is not safe against timing attacks. By repeatedly submitting invalid tokens, an attacker can brute-force the expected CSRF token character by character. Once they have recovered the token, they can then submit a forged request on behalf of a logged-in user and execute privileged actions on that user’s behalf. In particular the function to validate received CSRF tokens is at oppia.core.controllers.base.CsrfTokenManager.is_csrf_token_valid
. An attacker who can lure a logged-in Oppia user to a malicious website can perform any change on Oppia that the user is authorized to do, including changing profile information; creating, deleting, and changing explorations; etc. Note that the attacker cannot change a user’s login credentials. An attack would need to complete within 1 second because every second, the time used in computing the token changes. This issue has been addressed in commit b89bf80837
which has been included in release 3.3.2-hotfix-2
. Users are advised to upgrade. There are no known workarounds for this vulnerability.
5.3 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
7.1 High
AI Score
Confidence
High
0.001 Low
EPSS
Percentile
22.0%