CVE - CVE-2023-40021

CVE-ID
CVE-2023-40021	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
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.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://github.com/oppia/oppia/blob/3a05c3558a292f3db9e658e60e708c266c003fd0/core/controllers/base.py#L964-L990 URL:https://github.com/oppia/oppia/blob/3a05c3558a292f3db9e658e60e708c266c003fd0/core/controllers/base.py#L964-L990 MISC:https://github.com/oppia/oppia/commit/b89bf808378c1236874b5797a7bda32c77b4af23 URL:https://github.com/oppia/oppia/commit/b89bf808378c1236874b5797a7bda32c77b4af23 MISC:https://github.com/oppia/oppia/pull/18769 URL:https://github.com/oppia/oppia/pull/18769 MISC:https://github.com/oppia/oppia/security/advisories/GHSA-49jp-pjc3-2532 URL:https://github.com/oppia/oppia/security/advisories/GHSA-49jp-pjc3-2532
Assigning CNA
GitHub (maintainer security advisories)
Date Record Created
20230808	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20230808)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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