CWE-295 Base Brouillon

Improper Certificate Validation

This vulnerability occurs when an application fails to properly verify the authenticity of a digital certificate, or performs the verification incorrectly, allowing untrusted connections to appear…

Définition

What is CWE-295?

This vulnerability occurs when an application fails to properly verify the authenticity of a digital certificate, or performs the verification incorrectly, allowing untrusted connections to appear legitimate.

Digital certificates act like digital passports for servers and services, proving their identity. When an application doesn't rigorously check these certificates—for example, by accepting self-signed certificates, ignoring expiration dates, or not validating the certificate chain back to a trusted root—it can mistakenly connect to a malicious server impersonating a legitimate one. This creates a critical opening for man-in-the-middle (MitM) attacks where attackers can intercept, read, or modify sensitive data in transit. To prevent this, developers must ensure their code enforces strict certificate validation. This means always verifying the certificate's signature chain against a trusted root certificate authority (CA), checking the hostname matches, and ensuring the certificate is valid and not revoked. Relying on default settings is often insufficient; explicit configuration in libraries for TLS/SSL connections is typically required to reject invalid certificates and maintain a secure communication channel.

Vulnerability Diagram CWE-295

Impact réel

Real-world CVEs caused by CWE-295

CVE-2019-12496

A Go framework for robotics, drones, and IoT devices skips verification of root CA certificates by default.
CVE-2014-1266

chain: incorrect "goto" in Apple SSL product bypasses certificate validation, allowing Adversary-in-the-Middle (AITM) attack (Apple "goto fail" bug). CWE-705 (Incorrect Control Flow Scoping) -> CWE-561 (Dead Code) -> CWE-295 (Improper Certificate Validation) -> CWE-393 (Return of Wrong Status Code) -> CWE-300 (Channel Accessible by Non-Endpoint).
CVE-2021-22909

Chain: router's firmware update procedure uses curl with "-k" (insecure) option that disables certificate validation (CWE-295), allowing adversary-in-the-middle (AITM) compromise with a malicious firmware image (CWE-494).
CVE-2008-4989

Verification function trusts certificate chains in which the last certificate is self-signed.
CVE-2012-5821

Web browser uses a TLS-related function incorrectly, preventing it from verifying that a server's certificate is signed by a trusted certification authority (CA)
CVE-2009-3046

Web browser does not check if any intermediate certificates are revoked.
CVE-2011-0199

Operating system does not check Certificate Revocation List (CRL) in some cases, allowing spoofing using a revoked certificate.
CVE-2012-5810

Mobile banking application does not verify hostname, leading to financial loss.

Comment les attaquants l'exploitent

Parcours de l'attaquant étape par étape

1
This code checks the certificate of a connected peer.
2
In this case, because the certificate is self-signed, there was no external authority that could prove the identity of the host. The program could be communicating with a different system that is spoofing the host, e.g. by poisoning the DNS cache or using an Adversary-in-the-Middle (AITM) attack to modify the traffic from server to client.
3
The following OpenSSL code obtains a certificate and verifies it.
4
Even though the "verify" step returns X509_V_OK, this step does not include checking the Common Name against the name of the host. That is, there is no guarantee that the certificate is for the desired host. The SSL connection could have been established with a malicious host that provided a valid certificate.
5
The following OpenSSL code ensures that there is a certificate and allows the use of expired certificates.

Exemple de code vulnérable

Vulnerable C

This code checks the certificate of a connected peer.

Vulnérable C

if ((cert = SSL_get_peer_certificate(ssl)) && host)
  	foo=SSL_get_verify_result(ssl);
  if ((X509_V_OK==foo) || X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN==foo))
```
// certificate looks good, host can be trusted*

Exemple de code sécurisé

Secure pseudo

Sécurisé 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-295

Architecture and Design / Implementation Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key.
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 hostname.

Signaux de détection

How to detect CWE-295

Automated Static Analysis - Binary or Bytecode SOAR Partial

According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Bytecode Weakness Analysis - including disassembler + source code weakness analysis Binary Weakness Analysis - including disassembler + source code weakness analysis

Manual Static Analysis - Binary or Bytecode SOAR Partial

According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Dynamic Analysis with Automated Results Interpretation SOAR Partial

According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Web Application Scanner

Dynamic Analysis with Manual Results Interpretation High

According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Man-in-the-middle attack tool

Manual Static Analysis - Source Code High

According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Focused Manual Spotcheck - Focused manual analysis of source Manual Source Code Review (not inspections)

Automated Static Analysis - Source Code SOAR Partial

According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Source code Weakness Analyzer Context-configured Source Code Weakness Analyzer

Correction automatique Plexicus

Plexicus détecte automatiquement CWE-295 et ouvre une PR de correction en moins de 60 secondes.

Codex Remedium analyse chaque commit, identifie cette faiblesse précise et livre une pull request prête à être relue avec le correctif. Pas de tickets. Pas de transferts.

Obtenir une démo Essayer Plexicus gratuitement

Questions fréquentes

Frequently asked questions

Qu'est-ce que CWE-295 ?

Quelle est la gravité de CWE-295 ?

MITRE n'a pas publié de note de probabilité d'exploitation pour cette faiblesse. Traitez-la comme un impact moyen jusqu'à ce que votre modèle de menace prouve le contraire.

Quels langages ou plateformes sont affectés par CWE-295 ?

MITRE lists the following affected platforms: Mobile.

Comment puis-je prévenir CWE-295 ?

Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key. If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the hostname.

Comment Plexicus détecte et corrige CWE-295 ?

Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-295 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-295 ?

MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/295.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.

Faiblesses associées

Weaknesses related to CWE-295

CWE-287 Parent

Improper Authentication

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CWE-1390 Frère

Weak Authentication

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Authentication Bypass by Spoofing

This weakness occurs when an application's authentication system can be tricked into accepting forged or manipulated credentials, allowing…

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Authentication Bypass by Capture-replay

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CWE-306 Frère

Missing Authentication for Critical Function

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Improper Restriction of Excessive Authentication Attempts

This vulnerability occurs when an application fails to properly limit how many times someone can attempt to log in or verify their…

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Weak Password Requirements

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Insufficiently Protected Credentials

This vulnerability occurs when an application handles sensitive credentials like passwords or API keys in an insecure way, making them…

CWE-640 Frère

Weak Password Recovery Mechanism for Forgotten Password

This vulnerability occurs when an application's password reset or recovery feature is poorly designed or implemented, allowing attackers…

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