CWE-1296 Base Incompleto

Incorrect Chaining or Granularity of Debug Components

This vulnerability occurs when hardware debug components, such as test ports and scan chains, are incorrectly connected or organized within a chip's design. This misconfiguration can create…

Definición

What is CWE-1296?

This vulnerability occurs when hardware debug components, such as test ports and scan chains, are incorrectly connected or organized within a chip's design. This misconfiguration can create unintended access paths, potentially exposing sensitive internal data or functions.
Modern chips incorporate specialized debug components like Test Access Ports (TAPs) for boundary scans, internal scan cells for stimulus/response testing, and custom tracing hubs for monitoring. If these elements are chained together incorrectly or organized with improper granularity during the design phase, it breaks the intended security model of the debug infrastructure. This design or synthesis error creates hidden backdoors or elevates access permissions within the chip. Attackers could exploit these flawed connections to bypass security controls, extract cryptographic keys, or manipulate the chip's internal state, turning vital debugging features into serious security liabilities.
Impacto en el mundo real

Real-world CVEs caused by CWE-1296

  • CVE-2017-18347

    Incorrect access control in RDP Level 1 on STMicroelectronics STM32F0 series devices allows physically present attackers to extract the device's protected firmware via a special sequence of Serial Wire Debug (SWD) commands because there is a race condition between full initialization of the SWD interface and the setup of flash protection.

  • CVE-2020-1791

    There is an improper authorization vulnerability in several smartphones. The system has a logic-judging error, and, under certain scenarios, a successful exploit could allow the attacker to switch to third desktop after a series of operations in ADB mode. (Vulnerability ID: HWPSIRT-2019-10114).

Cómo lo explotan los atacantes

Ruta del atacante paso a paso

  1. 1

    The following example shows how an attacker can take advantage of incorrect chaining or missing granularity of debug components.

  2. 2

    In a System-on-Chip (SoC), the user might be able to access the SoC-level TAP with a certain level of authorization. However, this access should not also grant access to all of the internal TAPs (e.g., Core). Separately, if any of the internal TAPs is also stitched to the TAP chain when it should not be because of a logic error, then an attacker can access the internal TAPs as well and execute commands there.

  3. 3

    As a related example, suppose there is a hierarchy of TAPs (TAP_A is connected to TAP_B and TAP_C, then TAP_B is connected to TAP_D and TAP_E, then TAP_C is connected to TAP_F and TAP_G, etc.). Architecture mandates that the user have one set of credentials for just accessing TAP_A, another set of credentials for accessing TAP_B and TAP_C, etc. However, if, during implementation, the designer mistakenly implements a daisy-chained TAP where all the TAPs are connected in a single TAP chain without the hierarchical structure, the correct granularity of debug components is not implemented and the attacker can gain unauthorized access.

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-1296

  • Implementation Ensure that debug components are properly chained and their granularity is maintained at different authentication levels.
Señales de detección

How to detect CWE-1296

Architecture or Design Review High

Appropriate Post-Si tests should be carried out at various authorization levels to ensure that debug components are properly chained and accessible only to users with appropriate credentials.

Dynamic Analysis with Manual Results Interpretation High

Appropriate Post-Si tests should be carried out at various authorization levels to ensure that debug components are properly chained and accessible only to users with appropriate credentials.

Auto-corrección de Plexicus

Plexicus detecta automáticamente CWE-1296 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-1296?

This vulnerability occurs when hardware debug components, such as test ports and scan chains, are incorrectly connected or organized within a chip's design. This misconfiguration can create unintended access paths, potentially exposing sensitive internal data or functions.

¿Qué gravedad tiene CWE-1296?

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-1296?

MITRE lists the following affected platforms: Verilog, VHDL, Not OS-Specific, Not Architecture-Specific, Processor Hardware, Not Technology-Specific.

¿Cómo puedo prevenir CWE-1296?

Ensure that debug components are properly chained and their granularity is maintained at different authentication levels.

¿Cómo detecta y corrige Plexicus CWE-1296?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-1296 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-1296?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/1296.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

Debilidades relacionadas

Weaknesses related to CWE-1296

CWE-284 Padre

Improper Access Control

The software fails to properly limit who can access a resource, allowing unauthorized users or systems to interact with it.

CWE-1191 Hermano

On-Chip Debug and Test Interface With Improper Access Control

This vulnerability occurs when a hardware chip's debug or test interface (like JTAG) lacks proper access controls. Without correct…

CWE-1220 Hermano

Insufficient Granularity of Access Control

This vulnerability occurs when a system's access controls are too broad, allowing unauthorized users or processes to read or modify…

CWE-1224 Hermano

Improper Restriction of Write-Once Bit Fields

This vulnerability occurs when hardware write-once protection mechanisms, often called 'sticky bits,' are incorrectly implemented,…

CWE-1231 Hermano

Improper Prevention of Lock Bit Modification

This vulnerability occurs when hardware or firmware uses a lock bit to protect critical system registers or memory regions, but fails to…

CWE-1233 Hermano

Security-Sensitive Hardware Controls with Missing Lock Bit Protection

This vulnerability occurs when a hardware device uses a lock bit to protect critical configuration registers, but the lock fails to…

CWE-1252 Hermano

CPU Hardware Not Configured to Support Exclusivity of Write and Execute Operations

This vulnerability occurs when a CPU's hardware is not set up to enforce a strict separation between writing data to memory and executing…

CWE-1257 Hermano

Improper Access Control Applied to Mirrored or Aliased Memory Regions

This vulnerability occurs when a hardware design maps the same physical memory to multiple addresses (aliasing or mirroring) but fails to…

CWE-1259 Hermano

Improper Restriction of Security Token Assignment

This vulnerability occurs when a System-on-a-Chip (SoC) fails to properly secure its Security Token mechanism. These tokens control which…

Recursos

Further reading

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