CWE-585: Empty Synchronized Block | Glexia
CWE-585 (Empty Synchronized Block) weakness overview with consequences, detection methods, mitigations, related CVEs and MITRE ATT&CK context.
Glexia's Take · Automated analysis
CWE-585: Empty Synchronized Block
Empty Synchronized Block represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Executive Impact
- Other: Other: An empty synchronized block will wait until nobody else is using the synchronizer being specified. While this may be part of the desired behavior, because you haven't protected the subsequent code by placing it inside the synchronized block, nothing is stopping somebody else from modifying whatever it was you were waiting for while you run the subsequent code.
Developer Pattern
CWE-585 is the kind of defect developers can usually prevent with explicit validation, safer framework defaults, and tests that exercise hostile input or unsafe state transitions.
Automation confidence
high confidence from CWE-585, 4.20.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Official CWE Definition
CWE-585: Empty Synchronized Block
The product contains an empty synchronized block.
An empty synchronized block does not actually accomplish any synchronization and may indicate a troubled section of code. An empty synchronized block can occur because code no longer needed within the synchronized block is commented out without removing the synchronized block.
Developer And Remediation Guidance
How teams prevent and detect this weakness
Causes
- 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. 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.
Remediation
- 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.
Detection
- Automated Static Analysis: 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.)
Mappings
Related CVEs, CWEs, and ATT&CK context
Related CWEs
ATT&CK Relevance
ATT&CK relevance is shown only when reviewed or responsibly inferred.