CWE-696 Classe Incompleto

Incorrect Behavior Order

This weakness occurs when a system executes multiple dependent actions in the wrong sequence, leading to unexpected and potentially vulnerable states.

Definição

What is CWE-696?

This weakness occurs when a system executes multiple dependent actions in the wrong sequence, leading to unexpected and potentially vulnerable states.
Think of this as a race condition in logic, not just in threads. When operations like initialization, validation, state updates, or cleanup happen out of order, the application can be left in an inconsistent state. For example, using a resource before it's properly initialized, checking permissions after granting access, or cleaning up a log file before writing an error entry can all open doors to security issues, crashes, or data corruption. Developers can prevent this by explicitly modeling and enforcing the required sequence of operations in their code. Using state machines, well-defined lifecycle hooks, or design patterns that mandate order (like dependency injection or builder patterns) can help. Always ask: 'What must happen before this step, and what depends on this step being complete?' Testing should include verifying behavior sequences under different conditions, not just individual function outputs.
Impacto no mundo real

Real-world CVEs caused by CWE-696

  • CVE-2019-9805

    Chain: Creation of the packet client occurs before initialization is complete (CWE-696) resulting in a read from uninitialized memory (CWE-908), causing memory corruption.

  • CVE-2007-5191

    file-system management programs call the setuid and setgid functions in the wrong order and do not check the return values, allowing attackers to gain unintended privileges

  • CVE-2007-1588

    C++ web server program calls Process::setuid before calling Process::setgid, preventing it from dropping privileges, potentially allowing CGI programs to be called with higher privileges than intended

  • CVE-2022-37734

    Chain: lexer in Java-based GraphQL server does not enforce maximum of tokens early enough (CWE-696), allowing excessive CPU consumption (CWE-1176)

Como os atacantes a exploram

Trajeto do atacante passo a passo

  1. 1

    The following code attempts to validate a given input path by checking it against an allowlist and then return the canonical path. In this specific case, the path is considered valid if it starts with the string "/safe_dir/".

  2. 2

    The problem with the above code is that the validation step occurs before canonicalization occurs. An attacker could provide an input path of "/safe_dir/../" that would pass the validation step. However, the canonicalization process sees the double dot as a traversal to the parent directory and hence when canonicized the path would become just "/".

  3. 3

    To avoid this problem, validation should occur after canonicalization takes place. In this case canonicalization occurs during the initialization of the File object. The code below fixes the issue.

  4. 4

    This function prints the contents of a specified file requested by a user.

  5. 5

    This code first reads a specified file into memory, then prints the file if the user is authorized to see its contents. The read of the file into memory may be resource intensive and is unnecessary if the user is not allowed to see the file anyway.

Exemplo de código vulnerável

Vulnerable Java

The following code attempts to validate a given input path by checking it against an allowlist and then return the canonical path. In this specific case, the path is considered valid if it starts with the string "/safe_dir/".

Vulnerável Java 
String path = getInputPath();
  if (path.startsWith("/safe_dir/"))
  {
  	File f = new File(path);
  	return f.getCanonicalPath();
  }
Exemplo de código seguro

Secure Java

To avoid this problem, validation should occur after canonicalization takes place. In this case canonicalization occurs during the initialization of the File object. The code below fixes the issue.

Seguro Java 
String path = getInputPath();
  File f = new File(path);
  if (f.getCanonicalPath().startsWith("/safe_dir/"))
  {
  	return f.getCanonicalPath();
  }
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-696

  • 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-696

SAST High

Executar análise estática (SAST) na base de código à procura do padrão inseguro no fluxo de dados.

DAST Moderate

Executar testes dinâmicos de segurança de aplicações (DAST) contra o endpoint em execução.

Runtime Moderate

Monitorizar os registos em tempo de execução para traços de exceção invulgares, input malformado ou tentativas de contornar a autorização.

Code review Moderate

Revisão de código: sinalizar qualquer novo código que trate input desta superfície sem usar os ajudantes validados do framework.

Correção automática do Plexicus

O Plexicus deteta automaticamente o CWE-696 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.

Obter uma demonstração Experimente o Plexicus gratuitamente
Perguntas frequentes

Frequently asked questions

O que é o CWE-696?

This weakness occurs when a system executes multiple dependent actions in the wrong sequence, leading to unexpected and potentially vulnerable states.

Qual a gravidade do CWE-696?

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-696?

A MITRE não especificou as plataformas afetadas por este CWE — pode aplicar-se à maioria das stacks de aplicações.

Como posso prevenir o CWE-696?

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-696?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-696 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-696?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/696.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.

Fraquezas relacionadas

Weaknesses related to CWE-696

CWE-691 Pai

Insufficient Control Flow Management

This vulnerability occurs when a program's execution flow isn't properly managed, allowing attackers to bypass critical checks, trigger…

CWE-1265 Irmão

Unintended Reentrant Invocation of Non-reentrant Code Via Nested Calls

This vulnerability occurs when a non-reentrant function is called, and during its execution, another call is triggered that unexpectedly…

CWE-1281 Irmão

Sequence of Processor Instructions Leads to Unexpected Behavior

Certain sequences of valid and invalid processor instructions can cause the CPU to lock up or behave unpredictably, often requiring a hard…

CWE-362 Irmão

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

A race condition occurs when multiple processes or threads access a shared resource simultaneously without proper coordination, creating a…

CWE-430 Irmão

Deployment of Wrong Handler

This vulnerability occurs when a system incorrectly assigns or routes an object to the wrong processing component.

CWE-431 Irmão

Missing Handler

This vulnerability occurs when a software component lacks the necessary code to properly handle an error or unexpected event.

CWE-662 Irmão

Improper Synchronization

This vulnerability occurs when a multi-threaded or multi-process application allows shared resources to be accessed by multiple threads or…

CWE-670 Irmão

Always-Incorrect Control Flow Implementation

This weakness occurs when a section of code is structured in a way that always executes incorrectly, regardless of input or conditions.…

CWE-705 Irmão

Incorrect Control Flow Scoping

This vulnerability occurs when a program fails to return execution to the correct point in the code after finishing a specific operation…

Recursos

Further reading

Pronto quando você estiver

Pare de pagar por desenvolvedor.
Comece a fechar o ciclo.

O Plexicus é o ASPM nativo de IA que verifica, filtra, corrige, pentesta e explica — de forma autónoma. Programadores ilimitados, repos ilimitados, ações de IA de utilização justa. Nível gratuito real, €269/mo anual quando estiver pronto.

Começar grátis Reservar uma demo