CWE-1296 Base Incomplete

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…

Definition

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.
Auswirkungen in der Praxis

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).

Wie Angreifer es ausnutzen

Angreiferpfad Schritt für Schritt

  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.

Verwundbares Codebeispiel

Vulnerable pseudo

MITRE hat kein Codebeispiel für diese CWE veröffentlicht. Das untenstehende Muster ist illustrativ — kanonische Referenzen findest du unter Ressourcen.

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

Secure pseudo

Sicher 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.
Präventions-Checkliste

How to prevent CWE-1296

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

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.

Plexicus Auto-Fix

Plexicus erkennt CWE-1296 automatisch und öffnet in unter 60 Sekunden einen Fix-PR.

Codex Remedium scannt jeden Commit, identifiziert genau diese Schwachstelle und liefert einen reviewer-ready Pull Request mit dem Patch. Keine Tickets. Keine Hand-offs.

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Häufig gestellte Fragen

Frequently asked questions

Was ist 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.

Wie gravierend ist CWE-1296?

MITRE hat für diese Schwachstelle keine Exploit-Wahrscheinlichkeit veröffentlicht. Behandle sie als mittlere Auswirkung, bis dein Threat Model anderes belegt.

Welche Sprachen oder Plattformen sind von CWE-1296 betroffen?

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

Wie kann ich CWE-1296 verhindern?

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

Wie erkennt und behebt Plexicus CWE-1296?

Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-1296 bei jedem Commit. Bei einem Treffer öffnet unser Codex-Remedium-Agent einen Fix-PR mit korrigiertem Code, Tests und einer einzeiligen Zusammenfassung für den Reviewer.

Wo erfahre ich mehr über CWE-1296?

MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/1296.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.

Verwandte Schwachstellen

Weaknesses related to CWE-1296

CWE-284 Parent

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 Sibling

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 Sibling

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 Sibling

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 Sibling

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 Sibling

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 Sibling

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 Sibling

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 Sibling

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…

Ressourcen

Further reading

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