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…

Definición

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 en el mundo real

Real-world CVEs caused by CWE-1315

Todavía no hay CVEs públicos enlazados a esta CWE en el catálogo de MITRE.

Cómo lo explotan los atacantes

Ruta del atacante paso a paso

  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.

Ejemplo de código vulnerable

Vulnerable pseudo

MITRE no ha publicado un ejemplo de código para esta CWE. El patrón siguiente es ilustrativo — consulta Recursos para referencias canónicas.

Vulnerable pseudo 
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
  // Untrusted input flows directly into the sensitive sink.
  return executeUnsafe(input);
}
Ejemplo 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 prevención

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.
Señales de detección

How to detect CWE-1315

SAST High

Ejecuta análisis estático (SAST) sobre el código buscando el patrón inseguro en el flujo de datos.

DAST Moderate

Ejecuta pruebas dinámicas de seguridad de aplicaciones (DAST) contra el endpoint en vivo.

Runtime Moderate

Vigila los logs en tiempo de ejecución para detectar trazas de excepción inusuales, entradas malformadas o intentos de bypass de autorización.

Code review Moderate

Revisión de código: marca cualquier código nuevo que maneje entrada desde esta superficie sin usar los helpers validados del framework.

Auto-corrección de Plexicus

Plexicus detecta automáticamente CWE-1315 y abre un PR de corrección en menos de 60 segundos.

Codex Remedium escanea cada commit, identifica esta debilidad concreta y entrega un pull request listo para revisión con el parche. Sin tickets. Sin traspasos.

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Preguntas frecuentes

Frequently asked questions

¿Qué es 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.

¿Qué gravedad tiene CWE-1315?

MITRE no ha publicado una calificación de probabilidad de explotación para esta debilidad. Trátala como de impacto medio hasta que tu modelo de amenazas demuestre lo contrario.

¿Qué lenguajes o plataformas se ven afectados por CWE-1315?

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

¿Cómo puedo prevenir 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…

¿Cómo detecta y corrige Plexicus CWE-1315?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-1315 en cada commit. Cuando hay coincidencia, nuestro agente Codex Remedium abre un PR de corrección con el código corregido, las pruebas y un resumen de una línea para el revisor.

¿Dónde puedo aprender más sobre CWE-1315?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/1315.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

Debilidades relacionadas

Weaknesses related to CWE-1315

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Recursos

Further reading

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