CWE-565 Base Incomplete

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 to verify that the cookie data is legitimate, unaltered, and…

Definition

What is CWE-565?

This vulnerability occurs when an application uses cookies to make security decisions—like granting access or changing settings—but fails to verify that the cookie data is legitimate, unaltered, and belongs to the current user.
Cookies are often used to store session identifiers, user preferences, or state information, but they are controlled by the client's browser. When an application blindly trusts cookie values without validating their integrity or checking if they match the authenticated user's session, attackers can forge or manipulate cookies to impersonate other users, escalate privileges, or bypass security controls. To prevent this, developers should treat all client-side data, including cookies, as untrusted input. Implement server-side validation for any cookie used in security decisions, use cryptographically signed or encrypted cookies to prevent tampering, and bind session cookies to specific user attributes (like IP address or user agent) to detect session hijacking attempts.
Vulnerability Diagram CWE-565
Reliance on Cookie Without Validation Attacker forges cookie isAdmin=true; user=alice App logic if (cookie.isAdmin) ok // no signing / HMAC // no server-side session trusts client value Admin access trivially granted Cookie value is treated as authoritative without integrity checks.
Auswirkungen in der Praxis

Real-world CVEs caused by CWE-565

  • CVE-2008-5784

    e-dating application allows admin privileges by setting the admin cookie to 1.

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 Java

The following code excerpt reads a value from a browser cookie to determine the role of the user.

Verwundbar Java 
Cookie[] cookies = request.getCookies();
  for (int i =0; i< cookies.length; i++) {
  	Cookie c = cookies[i];
  	if (c.getName().equals("role")) {
  		userRole = c.getValue();
  	}
  }
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-565

  • Architecture and Design Avoid using cookie data for a security-related decision.
  • Implementation Perform thorough input validation (i.e.: server side validation) on the cookie data if you're going to use it for a security related decision.
  • Architecture and Design Add integrity checks to detect tampering.
  • Architecture and Design Protect critical cookies from replay attacks, since cross-site scripting or other attacks may allow attackers to steal a strongly-encrypted cookie that also passes integrity checks. This mitigation applies to cookies that should only be valid during a single transaction or session. By enforcing timeouts, you may limit the scope of an attack. As part of your integrity check, use an unpredictable, server-side value that is not exposed to the client.
Erkennungssignale

How to detect CWE-565

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.)

Plexicus Auto-Fix

Plexicus erkennt CWE-565 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-565?

This vulnerability occurs when an application uses cookies to make security decisions—like granting access or changing settings—but fails to verify that the cookie data is legitimate, unaltered, and belongs to the current user.

Wie gravierend ist CWE-565?

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-565 betroffen?

MITRE hat für diese CWE keine betroffenen Plattformen spezifiziert — sie kann in den meisten Anwendungs-Stacks auftreten.

Wie kann ich CWE-565 verhindern?

Avoid using cookie data for a security-related decision. Perform thorough input validation (i.e.: server side validation) on the cookie data if you're going to use it for a security related decision.

Wie erkennt und behebt Plexicus CWE-565?

Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-565 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-565?

MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/565.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.

Verwandte Schwachstellen

Weaknesses related to CWE-565

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-472 Sibling

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…

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.

CWE-784 Child

Reliance on Cookies without Validation and Integrity Checking in a Security Decision

This vulnerability occurs when an application makes security decisions—like granting access or verifying identity—based solely on cookie…

Ressourcen

Further reading

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