CWE-585 Variant Draft

Empty Synchronized Block

An empty synchronized block is a Java code construct where a synchronized block exists but contains no executable statements inside it.

Definition

What is CWE-585?

An empty synchronized block is a Java code construct where a synchronized block exists but contains no executable statements inside it.
An empty synchronized block is a logic flaw that fails to provide any actual thread safety or mutual exclusion. While the synchronized keyword is present, the block does nothing to protect shared data or coordinate threads, leaving critical sections of your code vulnerable to race conditions and concurrency bugs. This issue often arises during code maintenance, such as when a developer comments out or removes the internal logic for debugging but forgets to remove the now-useless synchronization wrapper. It serves as a clear red flag for developers to review that section of code, as it either indicates missing functionality or unnecessary overhead that can harm performance without benefit.
Auswirkungen in der Praxis

Real-world CVEs caused by CWE-585

Bisher sind in MITREs Katalog keine öffentlichen CVE-Referenzen mit dieser CWE verknüpft.

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 attempts to synchronize on an object, but does not execute anything in the synchronized block. This does not actually accomplish anything and may be a sign that a programmer is wrestling with synchronization but has not yet achieved the result they intend.

Verwundbar Java 
synchronized(this) { }
Sicheres Codebeispiel

Secure Java

Instead, in a correct usage, the synchronized statement should contain procedures that access or modify data that is exposed to multiple threads. For example, consider a scenario in which several threads are accessing student records at the same time. The method which sets the student ID to a new value will need to make sure that nobody else is accessing this data at the same time and will require synchronization.

Sicher Java 
public void setID(int ID){
  	synchronized(this){
  		this.ID = ID;
  	}
  }
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-585

  • Implementation When you come across an empty synchronized statement, or a synchronized statement in which the code has been commented out, try to determine what the original intentions were and whether or not the synchronized block is still necessary.
Erkennungssignale

How to detect CWE-585

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-585 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-585?

An empty synchronized block is a Java code construct where a synchronized block exists but contains no executable statements inside it.

Wie gravierend ist CWE-585?

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-585 betroffen?

MITRE lists the following affected platforms: Java.

Wie kann ich CWE-585 verhindern?

When you come across an empty synchronized statement, or a synchronized statement in which the code has been commented out, try to determine what the original intentions were and whether or not the synchronized block is still necessary.

Wie erkennt und behebt Plexicus CWE-585?

Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-585 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-585?

MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/585.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.

Verwandte Schwachstellen

Weaknesses related to CWE-585

CWE-1071 Parent

Empty Code Block

An empty code block occurs when a section of source code, such as a conditional statement or function body, contains no executable…

CWE-1069 Sibling

Empty Exception Block

This weakness occurs when a try-catch or try-finally block is present but contains no code to handle the caught exception or perform…

Ressourcen

Further reading

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