CWE-270 Base Rascunho

Privilege Context Switching Error

This vulnerability occurs when an application fails to properly manage user permissions while moving between different security contexts, potentially allowing unauthorized actions.

Definição

What is CWE-270?

This vulnerability occurs when an application fails to properly manage user permissions while moving between different security contexts, potentially allowing unauthorized actions.
Think of this as a security guard who forgets to check their keys when moving between restricted areas. In software, this happens when a process or thread switches between different privilege levels—like going from a low-privilege user mode to a high-privilege kernel mode, or when handling data from different trust zones—but doesn't correctly reset or validate its access rights. The system might carry over elevated permissions from a previous task, creating a window where an attacker can execute code or access data they shouldn't have. For developers, the core issue is a broken trust boundary during state transitions. Common pitfalls include temporarily raising privileges for a specific task but failing to drop them immediately afterward, or incorrectly assuming a new context inherits a safe default. To prevent this, always adopt the principle of least privilege explicitly during context switches: deliberately set the required permissions for the new operation and never rely on implicit state. Audit any code that changes execution context, such as system calls, callback handlers, or data parsers, to ensure privilege cleanup is mandatory and fail-safe.
Impacto no mundo real

Real-world CVEs caused by CWE-270

  • CVE-2002-1688

    Web browser cross domain problem when user hits "back" button.

  • CVE-2003-1026

    Web browser cross domain problem when user hits "back" button.

  • CVE-2002-1770

    Cross-domain issue - third party product passes code to web browser, which executes it in unsafe zone.

  • CVE-2005-2263

    Run callback in different security context after it has been changed from untrusted to trusted. * note that "context switch before actions are completed" is one type of problem that happens frequently, espec. in browsers.

Como os atacantes a exploram

Trajeto do atacante passo a passo

  1. 1

    Identificar um caminho de código que trata input não confiável sem validação.

  2. 2

    Criar um payload que explora o comportamento inseguro — injeção, traversal, overflow ou abuso de lógica.

  3. 3

    Entregar o payload através de um pedido normal e observar a reação da aplicação.

  4. 4

    Iterar até que a resposta exponha dados, execute código do atacante ou escale privilégios.

Exemplo de código vulnerável

Vulnerable pseudo

A MITRE não publicou um exemplo de código para este CWE. O padrão abaixo é ilustrativo — consulte os Recursos para referências canónicas.

Vulnerável pseudo 
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
  // Untrusted input flows directly into the sensitive sink.
  return executeUnsafe(input);
}
Exemplo de código seguro

Secure pseudo

Seguro pseudo 
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
  const safe = validateAndEscape(input);
  return executeWithGuards(safe);
}
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-270

  • Architecture and Design / Operation Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
  • Architecture and Design / Operation Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.
  • Architecture and Design Consider following the principle of separation of privilege. Require multiple conditions to be met before permitting access to a system resource.
Sinais de deteção

How to detect CWE-270

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-270 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-270?

This vulnerability occurs when an application fails to properly manage user permissions while moving between different security contexts, potentially allowing unauthorized actions.

Qual a gravidade do CWE-270?

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-270?

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

Como posso prevenir o CWE-270?

Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software. Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need…

Como é que o Plexicus deteta e corrige o CWE-270?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-270 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-270?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/270.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.

Fraquezas relacionadas

Weaknesses related to CWE-270

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Incorrect Use of Privileged APIs

This vulnerability occurs when software incorrectly uses functions that require special permissions. Attackers can exploit these mistakes…

Recursos

Further reading

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