CWE-821: Incorrect Synchronization
Official CWE-821 CWE context with Glexia analysis, remediation guidance, related CVEs, and ATT&CK context.
Glexia's Take
CWE-821: Incorrect Synchronization
Incorrect Synchronization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Executive Impact
- Integrity,Confidentiality,Other: Modify Application Data,Read Application Data,Alter Execution Logic
Developer Pattern
CWE-821 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.
Confidence
high confidence from CWE-821, 4.20.
Official CWE Definition
CWE-821: Incorrect Synchronization
The product utilizes a shared resource in a concurrent manner, but it does not correctly synchronize access to the resource.
If access to a shared resource is not correctly synchronized, then the resource may not be in a state that is expected by the product. This might lead to unexpected or insecure behaviors, especially if an attacker can influence the shared resource.
Developer And Remediation Guidance
How teams prevent and detect this weakness
Causes
- Missing validation
- Unsafe defaults
- Insufficient authorization or memory-safety invariant
Remediation
- Use safe APIs
- Centralize the control
- Add regression tests
- Review logs and telemetry for attempted abuse
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
- CWE-1088: Synchronous Access of Remote Resource without Timeout
- CWE-1264: Hardware Logic with Insecure De-Synchronization between Control and Data Channels
- CWE-572: Call to Thread run() instead of start()
- CWE-574: EJB Bad Practices: Use of Synchronization Primitives
- CWE-662: Improper Synchronization
- CWE-662: Improper Synchronization
- CWE-662: Improper Synchronization
ATT&CK Relevance
ATT&CK relevance is shown only when reviewed or responsibly inferred.