CWE-396 Base Rascunho

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 insecure error handling logic.

Definição

What is CWE-396?

This weakness occurs when code catches a generic exception type like 'Exception' or 'Throwable', which can hide specific errors and create insecure error handling logic.
While it may seem cleaner to catch a broad exception like 'Exception' instead of writing multiple specific catch blocks, this practice is risky. It masks the true nature of errors, preventing you from handling different failure scenarios appropriately. Exceptions that deserve special recovery logic, or that shouldn't be caught at that point in the program, get lumped together and ignored. As your application evolves and starts throwing new, more specific exception types, this broad catch will silently swallow them all. This defeats the core purpose of a typed exception system, making your code less robust and secure over time. It often leads to complex, bug-prone error handling that can introduce vulnerabilities, as critical failures go unnoticed and unlogged.
Impacto no mundo real

Real-world CVEs caused by CWE-396

Ainda não há referências CVE públicas associadas a este CWE no catálogo da MITRE.

Como os atacantes a exploram

Trajeto do atacante passo a passo

  1. 1

    The following code excerpt handles three types of exceptions in an identical fashion.

  2. 2

    At first blush, it may seem preferable to deal with these exceptions in a single catch block, as follows:

  3. 3

    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.

Exemplo de código vulnerável

Vulnerable Java

At first blush, it may seem preferable to deal with these exceptions in a single catch block, as follows:

Vulnerável Java 
try {
  	doExchange();
  }
  catch (Exception e) {
  	logger.error("doExchange failed", e);
  }
Exemplo de código seguro

Secure Java

The following code excerpt handles three types of exceptions in an identical fashion.

Seguro Java 
try {
  	doExchange();
  }
  catch (IOException e) {
  	logger.error("doExchange failed", e);
  }
  catch (InvocationTargetException e) {
  		logger.error("doExchange failed", e);
  }
  catch (SQLException e) {
  		logger.error("doExchange failed", e);
  }
What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Lista de verificação de prevenção

How to prevent CWE-396

  • Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
  • Implementation Validate input at trust boundaries; use allowlists, not denylists.
  • Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
  • Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
  • Operation Monitor logs for the runtime signals listed in the next section.
Sinais de deteção

How to detect CWE-396

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.)

Correção automática do Plexicus

O Plexicus deteta automaticamente o CWE-396 e abre um PR de correção em menos de 60 segundos.

O Codex Remedium analisa cada commit, identifica esta fraqueza exata e entrega um pull request pronto para revisão com o patch. Sem tickets. Sem transferências.

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Perguntas frequentes

Frequently asked questions

O que é o CWE-396?

This weakness occurs when code catches a generic exception type like 'Exception' or 'Throwable', which can hide specific errors and create insecure error handling logic.

Qual a gravidade do CWE-396?

A MITRE não publicou uma classificação de probabilidade de exploração para esta fraqueza. Trate-a como impacto médio até o seu modelo de ameaças provar o contrário.

Que linguagens ou plataformas são afetadas pelo CWE-396?

MITRE lists the following affected platforms: C++, Java, C#, Python.

Como posso prevenir o CWE-396?

Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.

Como é que o Plexicus deteta e corrige o CWE-396?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-396 em cada commit. Quando é encontrada uma correspondência, o nosso agente Codex Remedium abre um PR de correção com o código corrigido, testes e um resumo de uma linha para o revisor.

Onde posso saber mais sobre o CWE-396?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/396.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.

Fraquezas relacionadas

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Recursos

Further reading

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