CVE-2023-40021 (GCVE-0-2023-40021)
Vulnerability from cvelistv5 – Published: 2023-08-16 20:25 – Updated: 2024-10-03 13:37
VLAI
EPSS
VEX
Title
Timing Attack Reveals CSRF Tokens in oppia
Summary
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.
Severity
5.3 (Medium)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-10-03 13:33 UTC
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://github.com/oppia/oppia/security/advisorie… | x_refsource_CONFIRM |
| https://github.com/oppia/oppia/pull/18769 | x_refsource_MISC |
| https://github.com/oppia/oppia/commit/b89bf808378… | x_refsource_MISC |
| https://github.com/oppia/oppia/blob/3a05c3558a292… | x_refsource_MISC |
Impacted products
{
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2024-08-02T18:24:54.658Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"name": "https://github.com/oppia/oppia/security/advisories/GHSA-49jp-pjc3-2532",
"tags": [
"x_refsource_CONFIRM",
"x_transferred"
],
"url": "https://github.com/oppia/oppia/security/advisories/GHSA-49jp-pjc3-2532"
},
{
"name": "https://github.com/oppia/oppia/pull/18769",
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://github.com/oppia/oppia/pull/18769"
},
{
"name": "https://github.com/oppia/oppia/commit/b89bf808378c1236874b5797a7bda32c77b4af23",
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://github.com/oppia/oppia/commit/b89bf808378c1236874b5797a7bda32c77b4af23"
},
{
"name": "https://github.com/oppia/oppia/blob/3a05c3558a292f3db9e658e60e708c266c003fd0/core/controllers/base.py#L964-L990",
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://github.com/oppia/oppia/blob/3a05c3558a292f3db9e658e60e708c266c003fd0/core/controllers/base.py#L964-L990"
}
],
"title": "CVE Program Container"
},
{
"affected": [
{
"cpes": [
"cpe:2.3:a:oppia:oppia:*:*:*:*:*:*:*:*"
],
"defaultStatus": "unknown",
"product": "oppia",
"vendor": "oppia",
"versions": [
{
"lessThan": "3.3.2",
"status": "affected",
"version": "1.1.0",
"versionType": "custom"
}
]
}
],
"metrics": [
{
"other": {
"content": {
"id": "CVE-2023-40021",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2024-10-03T13:33:01.578679Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2024-10-03T13:37:09.373Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "oppia",
"vendor": "oppia",
"versions": [
{
"status": "affected",
"version": "\u003e= 1.1.0, \u003c 3.3.2-hotfix-2"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "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\u0027s 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\u0027s 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": [
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 5.3,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-203",
"description": "CWE-203: Observable Discrepancy",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-208",
"description": "CWE-208: Observable Timing Discrepancy",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2023-08-16T20:25:22.726Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/oppia/oppia/security/advisories/GHSA-49jp-pjc3-2532",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/oppia/oppia/security/advisories/GHSA-49jp-pjc3-2532"
},
{
"name": "https://github.com/oppia/oppia/pull/18769",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/oppia/oppia/pull/18769"
},
{
"name": "https://github.com/oppia/oppia/commit/b89bf808378c1236874b5797a7bda32c77b4af23",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/oppia/oppia/commit/b89bf808378c1236874b5797a7bda32c77b4af23"
},
{
"name": "https://github.com/oppia/oppia/blob/3a05c3558a292f3db9e658e60e708c266c003fd0/core/controllers/base.py#L964-L990",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/oppia/oppia/blob/3a05c3558a292f3db9e658e60e708c266c003fd0/core/controllers/base.py#L964-L990"
}
],
"source": {
"advisory": "GHSA-49jp-pjc3-2532",
"discovery": "UNKNOWN"
},
"title": "Timing Attack Reveals CSRF Tokens in oppia"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2023-40021",
"datePublished": "2023-08-16T20:25:22.726Z",
"dateReserved": "2023-08-08T13:46:25.243Z",
"dateUpdated": "2024-10-03T13:37:09.373Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.1",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2023-40021",
"date": "2026-09-23",
"epss": "0.00774",
"percentile": "0.54289"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"product": "oppia",
"vendor": "oppia",
"versions": [
{
"status": "affected",
"version": "\u003e= 1.1.0, \u003c 3.3.2-hotfix-2"
}
]
}
],
"source": "security-advisories@github.com"
},
{
"affectedData": [
{
"cpes": [
"cpe:2.3:a:oppia:oppia:*:*:*:*:*:*:*:*"
],
"defaultStatus": "unknown",
"product": "oppia",
"vendor": "oppia",
"versions": [
{
"lessThan": "3.3.2",
"status": "affected",
"version": "1.1.0",
"versionType": "custom"
}
]
}
],
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:oppia:oppia:*:*:*:*:*:*:*:*",
"matchCriteriaId": "87F65B5D-6454-4E3C-A7A5-F1FEEC6DC78C",
"versionEndExcluding": "3.3.2",
"versionStartIncluding": "1.1.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:oppia:oppia:3.3.2:-:*:*:*:*:*:*",
"matchCriteriaId": "7B0060B6-6E1F-4B0F-8A6B-3437450C94C3",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "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\u0027s 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\u0027s 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."
}
],
"id": "CVE-2023-40021",
"lastModified": "2026-06-17T06:15:47.100",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 5.3,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N",
"version": "3.1"
},
"exploitabilityScore": 1.6,
"impactScore": 3.6,
"source": "security-advisories@github.com",
"type": "Secondary"
},
{
"cvssData": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 5.3,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N",
"version": "3.1"
},
"exploitabilityScore": 1.6,
"impactScore": 3.6,
"source": "nvd@nist.gov",
"type": "Primary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2023-40021",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2024-10-03T13:33:01.578679Z",
"version": "2.0.3"
}
}
]
},
"published": "2023-08-16T21:15:09.880",
"references": [
{
"source": "security-advisories@github.com",
"tags": [
"Product"
],
"url": "https://github.com/oppia/oppia/blob/3a05c3558a292f3db9e658e60e708c266c003fd0/core/controllers/base.py#L964-L990"
},
{
"source": "security-advisories@github.com",
"tags": [
"Patch"
],
"url": "https://github.com/oppia/oppia/commit/b89bf808378c1236874b5797a7bda32c77b4af23"
},
{
"source": "security-advisories@github.com",
"tags": [
"Patch"
],
"url": "https://github.com/oppia/oppia/pull/18769"
},
{
"source": "security-advisories@github.com",
"tags": [
"Exploit",
"Vendor Advisory"
],
"url": "https://github.com/oppia/oppia/security/advisories/GHSA-49jp-pjc3-2532"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"tags": [
"Product"
],
"url": "https://github.com/oppia/oppia/blob/3a05c3558a292f3db9e658e60e708c266c003fd0/core/controllers/base.py#L964-L990"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"tags": [
"Patch"
],
"url": "https://github.com/oppia/oppia/commit/b89bf808378c1236874b5797a7bda32c77b4af23"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"tags": [
"Patch"
],
"url": "https://github.com/oppia/oppia/pull/18769"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"tags": [
"Exploit",
"Vendor Advisory"
],
"url": "https://github.com/oppia/oppia/security/advisories/GHSA-49jp-pjc3-2532"
}
],
"sourceIdentifier": "security-advisories@github.com",
"vulnStatus": "Modified",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-203"
},
{
"lang": "en",
"value": "CWE-208"
}
],
"source": "security-advisories@github.com",
"type": "Secondary"
},
{
"description": [
{
"lang": "en",
"value": "CWE-203"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
},
"vulnrichment": {
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2024-08-02T18:24:54.658Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"name": "https://github.com/oppia/oppia/security/advisories/GHSA-49jp-pjc3-2532",
"tags": [
"x_refsource_CONFIRM",
"x_transferred"
],
"url": "https://github.com/oppia/oppia/security/advisories/GHSA-49jp-pjc3-2532"
},
{
"name": "https://github.com/oppia/oppia/pull/18769",
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://github.com/oppia/oppia/pull/18769"
},
{
"name": "https://github.com/oppia/oppia/commit/b89bf808378c1236874b5797a7bda32c77b4af23",
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://github.com/oppia/oppia/commit/b89bf808378c1236874b5797a7bda32c77b4af23"
},
{
"name": "https://github.com/oppia/oppia/blob/3a05c3558a292f3db9e658e60e708c266c003fd0/core/controllers/base.py#L964-L990",
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://github.com/oppia/oppia/blob/3a05c3558a292f3db9e658e60e708c266c003fd0/core/controllers/base.py#L964-L990"
}
],
"title": "CVE Program Container"
},
{
"affected": [
{
"cpes": [
"cpe:2.3:a:oppia:oppia:*:*:*:*:*:*:*:*"
],
"defaultStatus": "unknown",
"product": "oppia",
"vendor": "oppia",
"versions": [
{
"lessThan": "3.3.2",
"status": "affected",
"version": "1.1.0",
"versionType": "custom"
}
]
}
],
"metrics": [
{
"other": {
"content": {
"id": "CVE-2023-40021",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2024-10-03T13:33:01.578679Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2024-10-03T13:33:56.674Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "oppia",
"vendor": "oppia",
"versions": [
{
"status": "affected",
"version": "\u003e= 1.1.0, \u003c 3.3.2-hotfix-2"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "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\u0027s 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\u0027s 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": [
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 5.3,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-203",
"description": "CWE-203: Observable Discrepancy",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-208",
"description": "CWE-208: Observable Timing Discrepancy",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2023-08-16T20:25:22.726Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/oppia/oppia/security/advisories/GHSA-49jp-pjc3-2532",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/oppia/oppia/security/advisories/GHSA-49jp-pjc3-2532"
},
{
"name": "https://github.com/oppia/oppia/pull/18769",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/oppia/oppia/pull/18769"
},
{
"name": "https://github.com/oppia/oppia/commit/b89bf808378c1236874b5797a7bda32c77b4af23",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/oppia/oppia/commit/b89bf808378c1236874b5797a7bda32c77b4af23"
},
{
"name": "https://github.com/oppia/oppia/blob/3a05c3558a292f3db9e658e60e708c266c003fd0/core/controllers/base.py#L964-L990",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/oppia/oppia/blob/3a05c3558a292f3db9e658e60e708c266c003fd0/core/controllers/base.py#L964-L990"
}
],
"source": {
"advisory": "GHSA-49jp-pjc3-2532",
"discovery": "UNKNOWN"
},
"title": "Timing Attack Reveals CSRF Tokens in oppia"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2023-40021",
"datePublished": "2023-08-16T20:25:22.726Z",
"dateReserved": "2023-08-08T13:46:25.243Z",
"dateUpdated": "2024-10-03T13:37:09.373Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.1"
}
}
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
Loading…