CWE-297 Variant Incomplete High likelihood

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 the specific host it's connecting to. Even a correctly signed…

Definition

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.
Auswirkungen in der Praxis

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.

Wie Angreifer es ausnutzen

Angreiferpfad Schritt für Schritt

  1. 1

    Identifiziere einen Codepfad, der nicht vertrauenswürdige Eingaben ohne Validierung verarbeitet.

  2. 2

    Erzeuge eine Payload, die das unsichere Verhalten auslöst — Injection, Traversal, Overflow oder Logik-Missbrauch.

  3. 3

    Liefere die Payload über einen normalen Request aus und beobachte die Reaktion der Anwendung.

  4. 4

    Iteriere, bis die Antwort Daten preisgibt, Angreifer-Code ausführt oder Berechtigungen eskaliert.

Verwundbares Codebeispiel

Vulnerable C

The following OpenSSL code obtains a certificate and verifies it.

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

Secure pseudo

Sicher 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.
Präventions-Checkliste

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.
Erkennungssignale

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.

Plexicus Auto-Fix

Plexicus erkennt CWE-297 automatisch und öffnet in unter 60 Sekunden einen Fix-PR.

Codex Remedium scannt jeden Commit, identifiziert genau diese Schwachstelle und liefert einen reviewer-ready Pull Request mit dem Patch. Keine Tickets. Keine Hand-offs.

Demo anfordern Plexicus kostenlos testen
Häufig gestellte Fragen

Frequently asked questions

Was ist 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.

Wie gravierend ist CWE-297?

MITRE stuft die Exploit-Wahrscheinlichkeit als hoch ein — diese Schwachstelle wird aktiv in freier Wildbahn ausgenutzt und sollte priorisiert behoben werden.

Welche Sprachen oder Plattformen sind von CWE-297 betroffen?

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

Wie kann ich CWE-297 verhindern?

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.

Wie erkennt und behebt Plexicus CWE-297?

Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-297 bei jedem Commit. Bei einem Treffer öffnet unser Codex-Remedium-Agent einen Fix-PR mit korrigiertem Code, Tests und einer einzeiligen Zusammenfassung für den Reviewer.

Wo erfahre ich mehr über CWE-297?

MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/297.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.

Verwandte Schwachstellen

Weaknesses related to CWE-297

CWE-923 Parent

Improper Restriction of Communication Channel to Intended Endpoints

This vulnerability occurs when a system opens a communication channel for a sensitive task but fails to properly verify that it's actually…

CWE-1275 Sibling

Sensitive Cookie with Improper SameSite Attribute

This vulnerability occurs when a sensitive cookie does not have a secure SameSite attribute configured, leaving it exposed to cross-site…

CWE-291 Sibling

Reliance on IP Address for Authentication

This vulnerability occurs when a system uses a client's IP address as the sole or primary method to verify their identity.

CWE-300 Sibling

Channel Accessible by Non-Endpoint

This vulnerability occurs when a system fails to properly verify who is on the other end of a communication link or to secure the channel…

CWE-419 Sibling

Unprotected Primary Channel

This vulnerability occurs when an application exposes a privileged administrative interface or restricted functionality through a primary…

CWE-420 Sibling

Unprotected Alternate Channel

This vulnerability occurs when an application secures its main communication path but leaves a backup or alternative channel with weaker…

CWE-940 Sibling

Improper Verification of Source of a Communication Channel

This vulnerability occurs when an application accepts incoming communication requests without properly checking where they originate from,…

CWE-941 Sibling

Incorrectly Specified Destination in a Communication Channel

This vulnerability occurs when an application establishes an outgoing communication channel but fails to correctly define or enforce the…

CWE-942 Sibling

Permissive Cross-domain Security Policy with Untrusted Domains

This vulnerability occurs when a web application's cross-domain security policy, like a Content Security Policy (CSP), explicitly allows…

Ressourcen

Further reading

Bereit, wenn du es bist

Schluss mit dem Bezahlen pro Entwickler.
Schließ den Kreislauf.

Plexicus ist die KI-native ASPM, die scannt, filtert, fixt, pentestet und erklärt — autonom. Unbegrenzte Entwickler, unbegrenzte Repos, Fair-Use-KI-Aktionen. Echter kostenloser Tarif, €269/mo jährlich, wenn du bereit bist.

Kostenlos starten Demo buchen