CWE-1315 Base Incompleto

Improper Setting of Bus Controlling Capability in Fabric End-point

This vulnerability occurs when a hardware fabric endpoint is incorrectly configured to grant bus controller privileges to a device that should only respond to requests. This allows an unauthorized…

Definição

What is CWE-1315?

This vulnerability occurs when a hardware fabric endpoint is incorrectly configured to grant bus controller privileges to a device that should only respond to requests. This allows an unauthorized device to initiate and control data transactions across the system bus.
Many modern system-on-chip (SoC) designs use reusable fabric endpoints with a configurable control bit. This bit determines whether a connected IP block (like a peripheral) can act only as a responder to requests, or if it can also act as a controller, initiating transactions to access other system components. While this flexibility aids hardware reuse, it introduces a critical security boundary. If this control bit is enabled by default in the hardware design, or if system firmware or software incorrectly sets it during operation, a peripheral intended to be passive gains unauthorized control over the system fabric. This compromised device can then read from or write to sensitive memory regions or other peripherals, leading to data exposure, privilege escalation, or a complete system takeover.
Impacto no mundo real

Real-world CVEs caused by CWE-1315

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

    A typical, phone platform consists of the main, compute core or CPU, a DRAM-memory chip, an audio codec, a baseband modem, a power-management-integrated circuit ("PMIC"), a connectivity (WiFi and Bluetooth) modem, and several other analog/RF components. The main CPU is the only component that can control transactions, and all the other components are responder-only devices. All the components implement a PCIe end-point to interface with the rest of the platform. The responder devices should have the bus-control-enable bit in the PCIe-end-point register set to 0 in hardware to prevent the devices from controlling transactions to the CPU or other peripherals.

  2. 2

    The audio-codec chip does not have the bus-controller-enable-register bit hardcoded to 0. There is no platform-firmware flow to verify that the bus-controller-enable bit is set to 0 in all responders.

  3. 3

    Audio codec can now master transactions to the CPU and other platform components. Potentially, it can modify assets in other platform components to subvert system security.

  4. 4

    Platform firmware includes a flow to check the configuration of bus-controller-enable bit in all responder devices. If this register bit is set on any of the responders, platform firmware sets it to 0. Ideally, the default value of this register bit should be hardcoded to 0 in RTL. It should also have access control to prevent untrusted entities from setting this bit to become bus controllers.

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-1315

  • Architecture and Design For responder devices, the register bit in the fabric end-point that enables the bus controlling capability must be set to 0 by default. This bit should not be set during secure-boot flows. Also, writes to this register must be access-protected to prevent malicious modifications to obtain bus-controlling capability.
  • Implementation For responder devices, the register bit in the fabric end-point that enables the bus controlling capability must be set to 0 by default. This bit should not be set during secure-boot flows. Also, writes to this register must be access-protected to prevent malicious modifications to obtain bus-controlling capability.
  • System Configuration For responder devices, the register bit in the fabric end-point that enables the bus controlling capability must be set to 0 by default. This bit should not be set during secure-boot flows. Also, writes to this register must be access-protected to prevent malicious modifications to obtain bus-controlling capability.
Sinais de deteção

How to detect CWE-1315

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-1315 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-1315?

This vulnerability occurs when a hardware fabric endpoint is incorrectly configured to grant bus controller privileges to a device that should only respond to requests. This allows an unauthorized device to initiate and control data transactions across the system bus.

Qual a gravidade do CWE-1315?

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-1315?

MITRE lists the following affected platforms: Not OS-Specific, Not Architecture-Specific, Not Technology-Specific.

Como posso prevenir o CWE-1315?

For responder devices, the register bit in the fabric end-point that enables the bus controlling capability must be set to 0 by default. This bit should not be set during secure-boot flows. Also, writes to this register must be access-protected to prevent malicious modifications to obtain bus-controlling capability. For responder devices, the register bit in the fabric end-point that enables the bus controlling capability must be set to 0 by default. This bit should not be set during…

Como é que o Plexicus deteta e corrige o CWE-1315?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-1315 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-1315?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/1315.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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