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.)
CWE-472 Base Draft
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…
Definition
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.
Auswirkungen in der Praxis
Real-world CVEs caused by CWE-472
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Forum product allows spoofed messages of other users via hidden form fields for name and e-mail address.
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Shopping cart allows price modification via hidden form field.
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Shopping cart allows price modification via hidden form field.
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Shopping cart allows price modification via hidden form field.
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Shopping cart allows price modification via hidden form field.
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Shopping cart allows price modification via hidden form field.
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Allows admin access by modifying value of form field.
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Read messages by modifying message ID parameter.
Wie Angreifer es ausnutzen
Angreiferpfad Schritt für Schritt
- 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
Hidden fields should not be trusted as secure parameters.
- 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
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.
Verwundbares Codebeispiel
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.
String accountID = request.getParameter("accountID");
User user = getUserFromID(Long.parseLong(accountID)); Sicheres Codebeispiel
Secure 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-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.
Erkennungssignale
How to detect CWE-472
Plexicus erkennt CWE-472 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.
Häufig gestellte Fragen Was ist CWE-472?
Wie gravierend ist CWE-472?
Welche Sprachen oder Plattformen sind von CWE-472 betroffen?
Wie kann ich CWE-472 verhindern?
Wie erkennt und behebt Plexicus CWE-472?
Wo erfahre ich mehr über CWE-472?
Frequently asked questions
Was ist 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.
Wie gravierend ist CWE-472?
MITRE hat für diese Schwachstelle keine Exploit-Wahrscheinlichkeit veröffentlicht. Behandle sie als mittlere Auswirkung, bis dein Threat Model anderes belegt.
Welche Sprachen oder Plattformen sind von CWE-472 betroffen?
MITRE hat für diese CWE keine betroffenen Plattformen spezifiziert — sie kann in den meisten Anwendungs-Stacks auftreten.
Wie kann ich CWE-472 verhindern?
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…
Wie erkennt und behebt Plexicus CWE-472?
Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-472 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-472?
MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/472.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.
Verwandte Schwachstellen
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 Sibling
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 Sibling
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 Sibling
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 Sibling
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.
Ressourcen
Further reading
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