CWE-396: Declaration of Catch for Generic Exception
Official CWE-396 CWE context with Glexia analysis, remediation guidance, related CVEs, and ATT&CK context.
Glexia's Take
CWE-396: Declaration of Catch for Generic Exception
Declaration of Catch for Generic Exception represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Executive Impact
- Non-Repudiation,Other: Hide Activities: A generic exception can hide details about unexpected adversary activities by making it difficult to properly troubleshoot error conditions during execution.
Developer Pattern
CWE-396 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-396, 4.20.
Official CWE Definition
CWE-396: Declaration of Catch for Generic Exception
Catching overly broad exceptions promotes complex error handling code that is more likely to contain security vulnerabilities.
Multiple catch blocks can get ugly and repetitive, but "condensing" catch blocks by catching a high-level class like Exception can obscure exceptions that deserve special treatment or that should not be caught at this point in the program. Catching an overly broad exception essentially defeats the purpose of a language's typed exceptions, and can become particularly dangerous if the program grows and begins to throw new types of exceptions. The new exception types will not receive any attention.
Developer And Remediation Guidance
How teams prevent and detect this weakness
Causes
- The following code excerpt handles three types of exceptions in an identical fashion. At first blush, it may seem preferable to deal with these exceptions in a single catch block, as follows:,However, if doExchange() is modified to throw a new type of exception that should be handled in some different kind of way, the broad catch block will prevent the compiler from pointing out the situation. Further, the new catch block will now also handle exceptions derived from RuntimeException such as ClassCastException, and NullPointerException, which is not the programmer's intent.
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
ATT&CK Relevance
ATT&CK relevance is shown only when reviewed or responsibly inferred.