CWE-1342 Base Incompleto

Information Exposure through Microarchitectural State after Transient Execution

This vulnerability occurs when a CPU fails to completely erase temporary data traces left behind by speculative execution or error recovery processes. These lingering microarchitectural hints can be…

Definição

What is CWE-1342?

This vulnerability occurs when a CPU fails to completely erase temporary data traces left behind by speculative execution or error recovery processes. These lingering microarchitectural hints can be analyzed through side-channels to leak sensitive information.
Modern CPUs use techniques like speculative execution and microcode assists to boost performance. When these operations are canceled or encounter errors, the processor should fully clean up. However, if remnants of these transient computations persist in internal buffers (like load/store queues), they create a measurable change in the chip's hidden state. An attacker can then use timing or other side-channel attacks to infer protected data, such as secrets from other processes or virtual machines. Successful exploitation typically requires three conditions: first, vulnerable code must speculatively access sensitive information, leaving microarchitectural traces. Second, the attacker must be able to trigger the specific CPU exceptions or mis-speculations that create these traces. Finally, the attacker needs a method to observe the state change, often by analyzing cache timing or other hardware resource contention, to slowly reconstruct the leaked data.
Impacto no mundo real

Real-world CVEs caused by CWE-1342

  • CVE-2020-0551

    Load value injection in some processors utilizing speculative execution may allow an authenticated user to enable information disclosure via a side-channel with local access.

Como os atacantes a exploram

Trajeto do atacante passo a passo

  1. 1

    Faulting loads in a victim domain may trigger incorrect transient forwarding, which leaves secret-dependent traces in the microarchitectural state. Consider this example from [REF-1203].

  2. 2

    Consider the code gadget:

  3. 3

    A processor with this weakness will store the value of untrusted_arg (which may be provided by an attacker) to the stack, which is trusted memory. Additionally, this store operation will save this value in some microarchitectural buffer, e.g. the store queue. In this code gadget, trusted_ptr is dereferenced while the attacker forces a page fault. The faulting load causes the processor to mis-speculate by forwarding untrusted_arg as the (speculative) load result. The processor then uses untrusted_arg for the pointer dereference. After the fault has been handled and the load has been re-issued with the correct argument, secret-dependent information stored at the address of trusted_ptr remains in microarchitectural state and can be extracted by an attacker using a code gadget.

Exemplo de código vulnerável

Vulnerable C

Consider the code gadget:

Vulnerável C 
void call_victim(size_t untrusted_arg) {
  	 *arg_copy = untrusted_arg;
  	 array[**trusted_ptr * 4096];
   }
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-1342

  • Architecture and Design / Requirements Hardware ensures that no illegal data flows from faulting micro-ops exists at the microarchitectural level.
  • Build and Compilation Include instructions that explicitly remove traces of unneeded computations from software interactions with microarchitectural elements e.g. lfence, sfence, mfence, clflush.
Sinais de deteção

How to detect CWE-1342

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-1342 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-1342?

This vulnerability occurs when a CPU fails to completely erase temporary data traces left behind by speculative execution or error recovery processes. These lingering microarchitectural hints can be analyzed through side-channels to leak sensitive information.

Qual a gravidade do CWE-1342?

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-1342?

MITRE lists the following affected platforms: Not OS-Specific, Workstation, x86, ARM, Other, Not Technology-Specific, System on Chip.

Como posso prevenir o CWE-1342?

Hardware ensures that no illegal data flows from faulting micro-ops exists at the microarchitectural level. Include instructions that explicitly remove traces of unneeded computations from software interactions with microarchitectural elements e.g. lfence, sfence, mfence, clflush.

Como é que o Plexicus deteta e corrige o CWE-1342?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-1342 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-1342?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/1342.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.

Fraquezas relacionadas

Weaknesses related to CWE-1342

CWE-226 Pai

Sensitive Information in Resource Not Removed Before Reuse

This vulnerability occurs when a system releases a resource like memory or a file for reuse but fails to erase the sensitive data it…

CWE-1239 Irmão

Improper Zeroization of Hardware Register

This vulnerability occurs when a hardware component fails to properly erase sensitive data from its internal registers before a new user…

CWE-1272 Irmão

Sensitive Information Uncleared Before Debug/Power State Transition

This vulnerability occurs when a device changes its power mode or enters a debug state but fails to wipe sensitive data that should become…

CWE-1301 Irmão

Insufficient or Incomplete Data Removal within Hardware Component

The product's data removal process fails to completely erase all data from hardware components, potentially leaving sensitive information…

CWE-244 Irmão

Improper Clearing of Heap Memory Before Release ('Heap Inspection')

Using realloc() to resize buffers containing secrets like passwords or keys can leave that sensitive data exposed in memory, as the…

Recursos

Further reading

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