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CVE-2023-40021 Detail

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.


Metrics

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CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/oppia/oppia/blob/3a05c3558a292f3db9e658e60e708c266c003fd0/core/controllers/base.py#L964-L990 Product 
https://github.com/oppia/oppia/blob/3a05c3558a292f3db9e658e60e708c266c003fd0/core/controllers/base.py#L964-L990 Product 
https://github.com/oppia/oppia/commit/b89bf808378c1236874b5797a7bda32c77b4af23 Patch 
https://github.com/oppia/oppia/commit/b89bf808378c1236874b5797a7bda32c77b4af23 Patch 
https://github.com/oppia/oppia/pull/18769 Patch 
https://github.com/oppia/oppia/pull/18769 Patch 
https://github.com/oppia/oppia/security/advisories/GHSA-49jp-pjc3-2532 Exploit  Vendor Advisory 
https://github.com/oppia/oppia/security/advisories/GHSA-49jp-pjc3-2532 Exploit  Vendor Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-203 Observable Discrepancy cwe source acceptance level NIST   GitHub, Inc.  
CWE-208 Observable Timing Discrepancy GitHub, Inc.  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

3 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2023-40021
NVD Published Date:
08/16/2023
NVD Last Modified:
11/21/2024
Source:
GitHub, Inc.