Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
CWE-299 Base Brouillon
Improper Check for Certificate Revocation
This vulnerability occurs when an application fails to properly verify whether a security certificate has been revoked, potentially allowing it to accept and use a compromised or untrustworthy…
Définition
What is CWE-299?
This vulnerability occurs when an application fails to properly verify whether a security certificate has been revoked, potentially allowing it to accept and use a compromised or untrustworthy certificate.
Failing to check certificate revocation is a critical security gap, more severe than other certificate errors. When a certificate is revoked, it's almost always because the associated private key has been exposed or the issuing authority no longer trusts it—meaning any system still using that certificate is likely compromised. Legitimate services should never operate with a revoked certificate unless they have a serious configuration or synchronization problem.
For developers, this means your application could mistakenly trust a malicious actor impersonating a legitimate server. To prevent this, always implement and test proper revocation checking mechanisms like CRL (Certificate Revocation List) or OCSP (Online Certificate Status Protocol) in your TLS/SSL handshake logic, and ensure these checks cannot be bypassed by network errors or performance shortcuts.
Impact réel
Real-world CVEs caused by CWE-299
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LDAP-over-SSL implementation does not check Certificate Revocation List (CRL), allowing spoofing using a revoked certificate.
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Operating system does not check Certificate Revocation List (CRL) in some cases, allowing spoofing using a revoked certificate.
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Antivirus product does not check whether certificates from signed executables have been revoked.
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Web browser does not check if any intermediate certificates are revoked.
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chain: Ruby module for OCSP misinterprets a response, preventing detection of a revoked certificate.
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chain: incorrect parsing of replies from OCSP responders allows bypass using a revoked certificate.
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Router can permanently cache certain public keys, which would allow bypass if the certificate is later revoked.
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chain: OS package manager does not properly check the return value, allowing bypass using a revoked certificate.
Comment les attaquants l'exploitent
Parcours de l'attaquant étape par étape
- 1
Identifier un chemin de code qui traite des entrées non fiables sans validation.
- 2
Élaborer une charge utile qui exploite le comportement non sécurisé — injection, traversal, débordement ou abus de logique.
- 3
Délivrer la charge utile via une requête normale et observer la réaction de l'application.
- 4
Itérer jusqu'à ce que la réponse divulgue des données, exécute le code de l'attaquant ou élève les privilèges.
Exemple de code vulnérable
Vulnerable C
The following OpenSSL code ensures that there is a certificate before continuing execution.
if (cert = SSL_get_peer_certificate(ssl)) {
```
// got a certificate, do secret things* Exemple de code sécurisé
Secure pseudo
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
const safe = validateAndEscape(input);
return executeWithGuards(safe);
} What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Liste de contrôle de prévention
How to prevent CWE-299
- Architecture and Design Ensure that certificates are checked for revoked status.
- Implementation If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the revoked status.
Signaux de détection
How to detect CWE-299
CWE-299
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Questions fréquentes Qu'est-ce que CWE-299 ?
Quelle est la gravité de CWE-299 ?
Quels langages ou plateformes sont affectés par CWE-299 ?
Comment puis-je prévenir CWE-299 ?
Comment Plexicus détecte et corrige CWE-299 ?
Où puis-je en savoir plus sur CWE-299 ?
Frequently asked questions
Qu'est-ce que CWE-299 ?
This vulnerability occurs when an application fails to properly verify whether a security certificate has been revoked, potentially allowing it to accept and use a compromised or untrustworthy certificate.
Quelle est la gravité de CWE-299 ?
MITRE évalue la probabilité d'exploitation comme Moyenne — l'exploitation est réaliste mais nécessite généralement des conditions spécifiques.
Quels langages ou plateformes sont affectés par CWE-299 ?
MITRE n'a pas spécifié les plateformes affectées pour ce CWE — il peut s'appliquer à la plupart des stacks applicatives.
Comment puis-je prévenir CWE-299 ?
Ensure that certificates are checked for revoked status. If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the revoked status.
Comment Plexicus détecte et corrige CWE-299 ?
Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-299 à chaque commit. Lorsqu'une correspondance est trouvée, notre agent Codex Remedium ouvre une PR de correction avec le code corrigé, les tests et un résumé d'une ligne pour le relecteur.
Où puis-je en savoir plus sur CWE-299 ?
MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/299.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.
Faiblesses associées
Weaknesses related to CWE-299
CWE-295 Parent
Improper Certificate Validation
This vulnerability occurs when an application fails to properly verify the authenticity of a digital certificate, or performs the…
CWE-296 Frère
Improper Following of a Certificate's Chain of Trust
This vulnerability occurs when software fails to properly validate the entire certificate chain back to a trusted root authority. This…
CWE-297 Frère
Improper Validation of Certificate with Host Mismatch
This vulnerability occurs when an application accepts a valid SSL/TLS certificate without properly verifying that it actually belongs to…
CWE-298 Frère
Improper Validation of Certificate Expiration
This vulnerability occurs when an application fails to properly check if a digital certificate has expired, potentially trusting…
CWE-599 Frère
Missing Validation of OpenSSL Certificate
This vulnerability occurs when an application uses OpenSSL but fails to properly verify server certificates by not calling…
CWE-370 Enfant
Missing Check for Certificate Revocation after Initial Check
This vulnerability occurs when software only verifies a certificate's revocation status once, then continues to trust it for subsequent…
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