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.
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…
Definição
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 no mundo real
Real-world CVEs caused by CWE-1296
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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.
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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).
Como os atacantes a exploram
Trajeto do atacante passo a passo
- 1
The following example shows how an attacker can take advantage of incorrect chaining or missing granularity of debug components.
- 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
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.
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.
// 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
// 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-1296
- Implementation Ensure that debug components are properly chained and their granularity is maintained at different authentication levels.
Sinais de deteção
How to detect CWE-1296
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.
CWE-1296
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Perguntas frequentes O que é o CWE-1296?
Qual a gravidade do CWE-1296?
Que linguagens ou plataformas são afetadas pelo CWE-1296?
Como posso prevenir o CWE-1296?
Como é que o Plexicus deteta e corrige o CWE-1296?
Onde posso saber mais sobre o CWE-1296?
Frequently asked questions
O que é o 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.
Qual a gravidade do CWE-1296?
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-1296?
MITRE lists the following affected platforms: Verilog, VHDL, Not OS-Specific, Not Architecture-Specific, Processor Hardware, Not Technology-Specific.
Como posso prevenir o CWE-1296?
Ensure that debug components are properly chained and their granularity is maintained at different authentication levels.
Como é que o Plexicus deteta e corrige o CWE-1296?
O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-1296 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-1296?
A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/1296.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.
Fraquezas relacionadas
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