Unauthenticated entity enumeration via unchecked OPTIONS requests
Published Jul 15, 2024 · Updated Aug 2, 2024
Authorization bypass in BusyKoala fastapi-opa before 2.0.1 allows remote attackers to enumerate application entities via HTTP OPTIONS requests. OpaMiddleware returns every OPTIONS request directly to the FastAPI application before authentication or Open Policy Agent evaluation. Exposure requires application routes whose OPTIONS responses differ by entity existence or writability, leaking those distinctions without credentials.
Summary
What happened
Authorization bypass in BusyKoala fastapi-opa before 2.0.1 allows remote attackers to enumerate application entities via HTTP OPTIONS requests. OpaMiddleware returns every OPTIONS request directly to the FastAPI application before authentication or Open Policy Agent evaluation. Exposure requires application routes whose OPTIONS responses differ by entity existence or writability, leaking those distinctions without credentials.
The record
- CVE
- CVE-2024-40627
- Published
- Jul 15, 2024
- Updated
- Aug 2, 2024
- Vendor
- BusyKoala
- Product
- fastapi-opa
- Classifications
- CWE-204, CAPEC-189, T1595
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 15, 2024CVE publishedPublication date reported by the CVE source.
- Aug 2, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <2.0.1
- Affected versionversion=< 2.0.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Maintainer OPTIONS entity-enumeration proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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