CWE-472 Base Brouillon

External Control of Assumed-Immutable Web Parameter

This vulnerability occurs when a web application incorrectly trusts data that appears to be fixed or hidden from the user, such as values in hidden form fields, cookies, or URL parameters. Because…

Définition

What is CWE-472?

This vulnerability occurs when a web application incorrectly trusts data that appears to be fixed or hidden from the user, such as values in hidden form fields, cookies, or URL parameters. Because this data is actually controllable by the client, attackers can modify it to bypass security checks or corrupt application logic.
Web applications often make a critical mistake: they assume that data sent to the client in hidden fields, cookies, or parameters will be returned unchanged. Since all client-side data can be tampered with, this false sense of security leads to improper validation. Attackers exploit this by modifying these assumed-immutable values to escalate privileges, manipulate prices, alter user sessions, or corrupt backend data flows. The core issue is the server's over-reliance on client-provided data for making security decisions. To prevent this, always validate and authorize all user input on the server, regardless of its perceived source or immutability. Treat hidden fields and cookies as untrusted input, just like any other form field. Implementing proper server-side session management and using cryptographic signatures for critical data can help enforce integrity. Managing these validation rules across a complex application is challenging; an ASPM platform like Plexicus can automatically detect these trust violations via DAST and SAST, and its AI can suggest precise code fixes to enforce server-side validation, streamlining remediation.
Impact réel

Real-world CVEs caused by CWE-472

  • CVE-2002-0108

    Forum product allows spoofed messages of other users via hidden form fields for name and e-mail address.

  • CVE-2000-0253

    Shopping cart allows price modification via hidden form field.

  • CVE-2000-0254

    Shopping cart allows price modification via hidden form field.

  • CVE-2000-0926

    Shopping cart allows price modification via hidden form field.

  • CVE-2000-0101

    Shopping cart allows price modification via hidden form field.

  • CVE-2000-0102

    Shopping cart allows price modification via hidden form field.

  • CVE-2000-0758

    Allows admin access by modifying value of form field.

  • CVE-2002-1880

    Read messages by modifying message ID parameter.

Comment les attaquants l'exploitent

Parcours de l'attaquant étape par étape

  1. 1

    In this example, a web application uses the value of a hidden form field (accountID) without having done any input validation because it was assumed to be immutable.

  2. 2

    Hidden fields should not be trusted as secure parameters.

  3. 3

    An attacker can intercept and alter hidden fields in a post to the server as easily as user input fields. An attacker can simply parse the HTML for the substring:

  4. 4

    or even just "hidden". Hidden field values displayed later in the session, such as on the following page, can open a site up to cross-site scripting attacks.

Exemple de code vulnérable

Vulnerable Java

In this example, a web application uses the value of a hidden form field (accountID) without having done any input validation because it was assumed to be immutable.

Vulnérable Java 
String accountID = request.getParameter("accountID");
  User user = getUserFromID(Long.parseLong(accountID));
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-472

  • Implementation Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
  • Implementation Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
Signaux de détection

How to detect CWE-472

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.)

Correction automatique Plexicus

Plexicus détecte automatiquement CWE-472 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-472 ?

This vulnerability occurs when a web application incorrectly trusts data that appears to be fixed or hidden from the user, such as values in hidden form fields, cookies, or URL parameters. Because this data is actually controllable by the client, attackers can modify it to bypass security checks or corrupt application logic.

Quelle est la gravité de CWE-472 ?

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-472 ?

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-472 ?

Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and…

Comment Plexicus détecte et corrige CWE-472 ?

Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-472 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-472 ?

MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/472.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.

Faiblesses associées

Weaknesses related to CWE-472

CWE-642 Parent

External Control of Critical State Data

This vulnerability occurs when an application stores security-sensitive state data in locations that unauthorized users can access and…

CWE-15 Frère

External Control of System or Configuration Setting

This vulnerability occurs when an application allows users to directly modify critical system settings or configuration values from an…

CWE-426 Frère

Untrusted Search Path

This vulnerability occurs when an application relies on an external search path, provided by a user or environment, to find and load…

CWE-565 Frère

Reliance on Cookies without Validation and Integrity Checking

This vulnerability occurs when an application uses cookies to make security decisions—like granting access or changing settings—but fails…

CWE-73 Frère

External Control of File Name or Path

This vulnerability occurs when an application uses unvalidated user input to construct file or directory paths for filesystem operations.

Ressources

Further reading

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