CWE-299 Base Borrador Medium likelihood

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This vulnerability occurs when an application fails to properly verify whether a security certificate has been revoked, potentially allowing it to accept and use a compromised or untrustworthy…

Definición

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This vulnerability occurs when an application fails to properly verify whether a security certificate has been revoked, potentially allowing it to accept and use a compromised or untrustworthy certificate.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.
Impacto en el mundo real

Real-world CVEs caused by CWE-299

  • CVE-2011-2014

    LDAP-over-SSL implementation does not check Certificate Revocation List (CRL), allowing spoofing using a revoked certificate.

  • CVE-2011-0199

    Operating system does not check Certificate Revocation List (CRL) in some cases, allowing spoofing using a revoked certificate.

  • CVE-2010-5185

    Antivirus product does not check whether certificates from signed executables have been revoked.

  • CVE-2009-3046

    Web browser does not check if any intermediate certificates are revoked.

  • CVE-2009-0161

    chain: Ruby module for OCSP misinterprets a response, preventing detection of a revoked certificate.

  • CVE-2011-2701

    chain: incorrect parsing of replies from OCSP responders allows bypass using a revoked certificate.

  • CVE-2011-0935

    Router can permanently cache certain public keys, which would allow bypass if the certificate is later revoked.

  • CVE-2009-1358

    chain: OS package manager does not properly check the return value, allowing bypass using a revoked certificate.

Cómo lo explotan los atacantes

Ruta del atacante paso a paso

  1. 1

    Identifica una ruta de código que maneje entrada no confiable sin validación.

  2. 2

    Crea un payload que ejercite el comportamiento inseguro — inyección, traversal, overflow o abuso de lógica.

  3. 3

    Envía el payload a través de una solicitud normal y observa la reacción de la aplicación.

  4. 4

    Itera hasta que la respuesta filtre datos, ejecute código del atacante o escale privilegios.

Ejemplo de código vulnerable

Vulnerable C

The following OpenSSL code ensures that there is a certificate before continuing execution.

Vulnerable C 
if (cert = SSL_get_peer_certificate(ssl)) {
```
// got a certificate, do secret things*
Ejemplo de código seguro

Secure pseudo

Seguro 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.
Lista de prevención

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.
Señales de detección

How to detect CWE-299

Automated Static Analysis High

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.)

Auto-corrección de Plexicus

Plexicus detecta automáticamente CWE-299 y abre un PR de corrección en menos de 60 segundos.

Codex Remedium escanea cada commit, identifica esta debilidad concreta y entrega un pull request listo para revisión con el parche. Sin tickets. Sin traspasos.

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Preguntas frecuentes

Frequently asked questions

¿Qué es 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.

¿Qué gravedad tiene CWE-299?

MITRE califica la probabilidad de explotación como Media — la explotación es realista pero suele requerir condiciones específicas.

¿Qué lenguajes o plataformas se ven afectados por CWE-299?

MITRE no ha especificado plataformas afectadas para esta CWE — puede aplicar a la mayoría de los stacks de aplicaciones.

¿Cómo puedo prevenir 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.

¿Cómo detecta y corrige Plexicus CWE-299?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-299 en cada commit. Cuando hay coincidencia, nuestro agente Codex Remedium abre un PR de corrección con el código corregido, las pruebas y un resumen de una línea para el revisor.

¿Dónde puedo aprender más sobre CWE-299?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/299.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

Debilidades relacionadas

Weaknesses related to CWE-299

CWE-295 Padre

Improper Certificate Validation

This vulnerability occurs when an application fails to properly verify the authenticity of a digital certificate, or performs the…

CWE-296 Hermano

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 Hermano

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 Hermano

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 Hermano

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 Hijo

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…

Recursos

Further reading

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