CWE-348 Base Brouillon

Use of Less Trusted Source

This vulnerability occurs when a system has access to multiple sources for the same critical data, but it chooses to rely on the less secure or less trustworthy one. This creates a security gap…

Définition

What is CWE-348?

This vulnerability occurs when a system has access to multiple sources for the same critical data, but it chooses to rely on the less secure or less trustworthy one. This creates a security gap because the system ignores better-protected alternatives that offer stronger verification or are harder for attackers to compromise.
Think of this flaw as a developer choosing to trust a rumor from an anonymous tip line over an official, signed document from a verified authority—even though both claim to state the same fact. The core issue isn't about missing data, but about making a poor choice between available sources. This often happens in code that fetches configuration, license keys, or critical parameters from multiple locations (like a local file, a network service, and a hardware security module) but defaults to the most convenient, rather than the most secure, option. To prevent this, your code should implement a clear trust hierarchy. Always design your system to prefer and require the most authoritative source—the one with the strongest cryptographic verification, integrity checks, or tamper resistance. This means explicitly validating the source before trusting its data and failing securely if the high-trust source is unavailable, rather than silently falling back to a weaker alternative that an attacker could easily manipulate.
Impact réel

Real-world CVEs caused by CWE-348

  • CVE-2001-0860

    Product uses IP address provided by a client, instead of obtaining it from the packet headers, allowing easier spoofing.

  • CVE-2004-1950

    Web product uses the IP address in the X-Forwarded-For HTTP header instead of a server variable that uses the connecting IP address, allowing filter bypass.

  • CVE-2001-0908

    Product logs IP address specified by the client instead of obtaining it from the packet headers, allowing information hiding.

  • CVE-2006-1126

    PHP application uses IP address from X-Forwarded-For HTTP header, instead of REMOTE_ADDR.

Comment les attaquants l'exploitent

Parcours de l'attaquant étape par étape

  1. 1

    This code attempts to limit the access of a page to certain IP Addresses. It checks the 'HTTP_X_FORWARDED_FOR' header in case an authorized user is sending the request through a proxy.

  2. 2

    The 'HTTP_X_FORWARDED_FOR' header can be user controlled and so should never be trusted. An attacker can falsify the header to gain access to the page.

  3. 3

    This fixed code only trusts the 'REMOTE_ADDR' header and so avoids the issue:

  4. 4

    Be aware that 'REMOTE_ADDR' can still be spoofed. This may seem useless because the server will send the response to the fake address and not the attacker, but this may still be enough to conduct an attack. For example, if the generatePage() function in this code is resource intensive, an attacker could flood the server with fake requests using an authorized IP and consume significant resources. This could be a serious DoS attack even though the attacker would never see the page's sensitive content.

Exemple de code vulnérable

Vulnerable PHP

This code attempts to limit the access of a page to certain IP Addresses. It checks the 'HTTP_X_FORWARDED_FOR' header in case an authorized user is sending the request through a proxy.

Vulnérable PHP 
$requestingIP = '0.0.0.0';
  if (array_key_exists('HTTP_X_FORWARDED_FOR', $_SERVER)) {
  	$requestingIP = $_SERVER['HTTP_X_FORWARDED_FOR'];
  else{
  	$requestingIP = $_SERVER['REMOTE_ADDR'];
  }
  if(in_array($requestingIP,$ipAllowlist)){
  	generatePage();
  	return;
  }
  else{
  	echo "You are not authorized to view this page";
  	return;
  }
Exemple de code sécurisé

Secure PHP

This fixed code only trusts the 'REMOTE_ADDR' header and so avoids the issue:

Sécurisé PHP 
$requestingIP = '0.0.0.0';
  if (array_key_exists('HTTP_X_FORWARDED_FOR', $_SERVER)) {
  	echo "This application cannot be accessed through a proxy.";
  	return;
  else{
  	$requestingIP = $_SERVER['REMOTE_ADDR'];
  }
```
...*
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-348

  • Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
  • Implementation Validate input at trust boundaries; use allowlists, not denylists.
  • Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
  • Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
  • Operation Monitor logs for the runtime signals listed in the next section.
Signaux de détection

How to detect CWE-348

SAST High

Exécuter une analyse statique (SAST) sur le code source à la recherche du motif non sécurisé dans le flux de données.

DAST Moderate

Exécuter des tests de sécurité applicative dynamique (DAST) contre le point de terminaison en ligne.

Runtime Moderate

Surveiller les journaux runtime pour détecter des traces d'exception inhabituelles, des entrées malformées ou des tentatives de contournement d'autorisation.

Code review Moderate

Revue de code : signaler tout nouveau code qui traite les entrées de cette surface sans utiliser les helpers du framework validés.

Correction automatique Plexicus

Plexicus détecte automatiquement CWE-348 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-348 ?

This vulnerability occurs when a system has access to multiple sources for the same critical data, but it chooses to rely on the less secure or less trustworthy one. This creates a security gap because the system ignores better-protected alternatives that offer stronger verification or are harder for attackers to compromise.

Quelle est la gravité de CWE-348 ?

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-348 ?

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-348 ?

Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.

Comment Plexicus détecte et corrige CWE-348 ?

Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-348 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-348 ?

MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/348.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.

Faiblesses associées

Weaknesses related to CWE-348

CWE-345 Parent

Insufficient Verification of Data Authenticity

This vulnerability occurs when an application fails to properly check where data comes from or confirm its legitimacy, allowing untrusted…

CWE-1293 Frère

Missing Source Correlation of Multiple Independent Data

This vulnerability occurs when a system trusts a single source of data without verification, making it impossible to detect if that source…

CWE-346 Frère

Origin Validation Error

This vulnerability occurs when an application fails to properly confirm the true origin of incoming data or communication, allowing…

CWE-347 Frère

Improper Verification of Cryptographic Signature

This vulnerability occurs when an application fails to properly check the digital signature on data, or skips the verification step…

CWE-349 Frère

Acceptance of Extraneous Untrusted Data With Trusted Data

This vulnerability occurs when a system processes both trusted and untrusted data together, but fails to separate them. The application…

CWE-351 Frère

Insufficient Type Distinction

This vulnerability occurs when an application fails to properly differentiate between different types of data or objects, leading to…

CWE-352 Frère

Cross-Site Request Forgery (CSRF)

Cross-Site Request Forgery (CSRF) happens when a web application cannot reliably tell if a user actually intended to submit a request,…

CWE-353 Frère

Missing Support for Integrity Check

This vulnerability occurs when a system uses a communication protocol that lacks built-in integrity verification, such as a checksum or…

CWE-354 Frère

Improper Validation of Integrity Check Value

This vulnerability occurs when software fails to properly check the integrity of data by validating its checksum or hash value. Without…

Ressources

Further reading

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