Overview
- 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.
- Source
- security-advisories@github.com
- NVD status
- Analyzed
Risk scores
CVSS 3.1
- Type
- Primary
- Base score
- 5.3
- Impact score
- 3.6
- Exploitability score
- 1.6
- Vector string
- CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
- Severity
- MEDIUM
Social media
- Hype score
- Not currently trending
Configurations
[
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:oppia:oppia:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "87F65B5D-6454-4E3C-A7A5-F1FEEC6DC78C",
"versionEndExcluding": "3.3.2",
"versionStartIncluding": "1.1.0"
},
{
"criteria": "cpe:2.3:a:oppia:oppia:3.3.2:-:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "7B0060B6-6E1F-4B0F-8A6B-3437450C94C3"
}
],
"operator": "OR"
}
]
}
]