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-584 Base Draft
Return Inside Finally Block
This vulnerability occurs when a function places a return statement inside a finally block. This dangerous pattern silently discards any unhandled exceptions thrown earlier in the try block, making…
Definition
What is CWE-584?
This vulnerability occurs when a function places a return statement inside a finally block. This dangerous pattern silently discards any unhandled exceptions thrown earlier in the try block, making errors invisible and undermining application stability.
A finally block is designed to execute cleanup code regardless of whether an exception occurs in the try or catch blocks. However, if you place a return statement inside finally, it overrides the normal exception propagation. When an exception is thrown in the try block but not caught before finally executes, the return in the finally block takes precedence. The function then exits normally, returning a value and completely discarding the original exception, as if the error never happened.
This creates a severe debugging and reliability issue because critical failure signals are lost. Developers are left with no stack trace, log entry, or indication that something went wrong, leading to silent data corruption, incorrect program states, and failures that are extremely difficult to diagnose. To avoid this, ensure return statements are placed in try or catch blocks, not in finally, and handle resource cleanup without altering the control flow for exceptions.
Auswirkungen in der Praxis
Real-world CVEs caused by CWE-584
Bisher sind in MITREs Katalog keine öffentlichen CVE-Referenzen mit dieser CWE verknüpft.
Wie Angreifer es ausnutzen
Angreiferpfad Schritt für Schritt
- 1
Identifiziere einen Codepfad, der nicht vertrauenswürdige Eingaben ohne Validierung verarbeitet.
- 2
Erzeuge eine Payload, die das unsichere Verhalten auslöst — Injection, Traversal, Overflow oder Logik-Missbrauch.
- 3
Liefere die Payload über einen normalen Request aus und beobachte die Reaktion der Anwendung.
- 4
Iteriere, bis die Antwort Daten preisgibt, Angreifer-Code ausführt oder Berechtigungen eskaliert.
Verwundbares Codebeispiel
Vulnerable Java
In the following code excerpt, the IllegalArgumentException will never be delivered to the caller. The finally block will cause the exception to be discarded.
try {
...
throw IllegalArgumentException();
}
finally {
return r;
} 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-584
- Implementation Do not use a return statement inside the finally block. The finally block should have "cleanup" code.
Erkennungssignale
How to detect CWE-584
Plexicus erkennt CWE-584 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-584?
Wie gravierend ist CWE-584?
Welche Sprachen oder Plattformen sind von CWE-584 betroffen?
Wie kann ich CWE-584 verhindern?
Wie erkennt und behebt Plexicus CWE-584?
Wo erfahre ich mehr über CWE-584?
Frequently asked questions
Was ist CWE-584?
This vulnerability occurs when a function places a return statement inside a finally block. This dangerous pattern silently discards any unhandled exceptions thrown earlier in the try block, making errors invisible and undermining application stability.
Wie gravierend ist CWE-584?
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-584 betroffen?
MITRE hat für diese CWE keine betroffenen Plattformen spezifiziert — sie kann in den meisten Anwendungs-Stacks auftreten.
Wie kann ich CWE-584 verhindern?
Do not use a return statement inside the finally block. The finally block should have "cleanup" code.
Wie erkennt und behebt Plexicus CWE-584?
Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-584 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-584?
MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/584.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.
Verwandte Schwachstellen
Weaknesses related to CWE-584
CWE-705 Parent
Incorrect Control Flow Scoping
This vulnerability occurs when a program fails to return execution to the correct point in the code after finishing a specific operation…
CWE-248 Sibling
Uncaught Exception
This vulnerability occurs when a function throws an error or exception, but the calling code does not have a proper handler to catch and…
CWE-382 Sibling
J2EE Bad Practices: Use of System.exit()
This vulnerability occurs when a J2EE application directly calls System.exit(), which forcibly terminates the entire application server…
CWE-395 Sibling
Use of NullPointerException Catch to Detect NULL Pointer Dereference
Using a try-catch block for NullPointerException as a substitute for proper null checks is an anti-pattern. This approach masks the root…
CWE-396 Sibling
Declaration of Catch for Generic Exception
This weakness occurs when code catches a generic exception type like 'Exception' or 'Throwable', which can hide specific errors and create…
CWE-397 Sibling
Declaration of Throws for Generic Exception
This vulnerability occurs when a method is declared to throw an overly broad exception type, such as a generic 'Exception' or 'Throwable'.…
CWE-455 Sibling
Non-exit on Failed Initialization
This vulnerability occurs when software continues to run as normal after encountering a critical security failure during its startup…
CWE-698 Sibling
Execution After Redirect (EAR)
Execution After Redirect (EAR) occurs when a web application sends a redirect response to a user's browser but continues to run…
Ressourcen
Further reading
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