CWE-297: Improper Validation of Certificate with Host Mismatch

Définition

What is CWE-297?

This vulnerability occurs when an application accepts a valid SSL/TLS certificate without properly verifying that it actually belongs to the specific host it's connecting to. Even a correctly signed certificate from a trusted authority can be misused if the hostname check is missing or flawed.

When your application connects to a server, it must verify that the certificate presented matches the intended hostname. This is done by checking the Common Name (CN) or, more reliably, the Subject Alternative Name (SAN) fields in the certificate. If this validation is skipped or implemented incorrectly, an attacker with a valid certificate for a different domain can impersonate your trusted service, leading to man-in-the-middle attacks and data interception. Common validation pitfalls include incomplete string comparisons that can be tricked by special characters, or failing to perform hostname checks when using certificate pinning. Always validate the hostname at the time of pinning and use established library functions for hostname verification instead of custom string matching, as these functions correctly handle edge cases like null bytes and wildcards.

Impact réel

Real-world CVEs caused by CWE-297

CVE-2012-5810

Mobile banking application does not verify hostname, leading to financial loss.
CVE-2012-5811

Mobile application for printing documents does not verify hostname, allowing attackers to read sensitive documents.
CVE-2012-5807

Software for electronic checking does not verify hostname, leading to financial loss.
CVE-2012-3446

Cloud-support library written in Python uses incorrect regular expression when matching hostname.
CVE-2009-2408

Web browser does not correctly handle '\0' character (NUL) in Common Name, allowing spoofing of https sites.
CVE-2012-0867

Database program truncates the Common Name during hostname verification, allowing spoofing.
CVE-2010-2074

Incorrect handling of '\0' character (NUL) in hostname verification allows spoofing.
CVE-2009-4565

Mail server's incorrect handling of '\0' character (NUL) in hostname verification allows spoofing.

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 obtains a certificate and verifies it.

Vulnérable C

cert = SSL_get_peer_certificate(ssl);
  if (cert && (SSL_get_verify_result(ssl)==X509_V_OK)) {
```
// do secret things* 
  		}

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-297

Architecture and Design Fully check the hostname of the certificate and provide the user with adequate information about the nature of the problem and how to proceed.
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-297

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.)

Dynamic Analysis with Manual Results Interpretation

Set up an untrusted endpoint (e.g. a server) with which the product will connect. Create a test certificate that uses an invalid hostname but is signed by a trusted CA and provide this certificate from the untrusted endpoint. If the product performs any operations instead of disconnecting and reporting an error, then this indicates that the hostname is not being checked and the test certificate has been accepted.

Black Box

When Certificate Pinning is being used in a mobile application, consider using a tool such as Spinner [REF-955]. This methodology might be extensible to other technologies.

CWE-297

Don't catalog this weakness. Prove it's reachable.

Plexicus turns CWE catalogs into evidence: every CWE-pattern is matched against your real code graph, reach is proven on a sandbox clone, and verified findings ship as reviewed PRs.

Request AI Swarm Pentest

Questions fréquentes

Frequently asked questions

Qu'est-ce que CWE-297 ?

This vulnerability occurs when an application accepts a valid SSL/TLS certificate without properly verifying that it actually belongs to the specific host it's connecting to. Even a correctly signed certificate from a trusted authority can be misused if the hostname check is missing or flawed.

Quelle est la gravité de CWE-297 ?

MITRE évalue la probabilité d'exploitation comme Élevée — cette faiblesse est activement exploitée et doit être priorisée pour la remédiation.

Quels langages ou plateformes sont affectés par CWE-297 ?

MITRE lists the following affected platforms: Mobile, Not Technology-Specific.

Comment puis-je prévenir CWE-297 ?

Fully check the hostname of the certificate and provide the user with adequate information about the nature of the problem and how to proceed. 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-297 ?

Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-297 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-297 ?

MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/297.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.

Faiblesses associées

Weaknesses related to CWE-297

CWE-923 Parent

Prêt à valider ce qui compte.

Plexicus est Proof-Driven AppSec : findings validés, compréhension contextuelle et remédiation relue — ancrée dans la preuve, scopée avec vous.

Réserver un Pentest

Improper Validation of Certificate with Host Mismatch

What is CWE-297?

Real-world CVEs caused by CWE-297

Parcours de l'attaquant étape par étape

Vulnerable C

Secure pseudo

How to prevent CWE-297

How to detect CWE-297

Don't catalog this weakness. Prove it's reachable.

Frequently asked questions

Weaknesses related to CWE-297

Improper Restriction of Communication Channel to Intended Endpoints

Sensitive Cookie with Improper SameSite Attribute

Reliance on IP Address for Authentication

Channel Accessible by Non-Endpoint

Unprotected Primary Channel

Unprotected Alternate Channel

Improper Verification of Source of a Communication Channel

Incorrectly Specified Destination in a Communication Channel

Permissive Cross-domain Security Policy with Untrusted Domains

Further reading

Prêt à valider ce qui compte.

Vérifiez si l'AI Swarm Pentest convient à votre environnement.

Demande reçue. Réservez la prochaine étape.

Sample evidence handover

Server-Side Request Forgery in `webhooks/receiver`