CWE-1276 Base Incomplete

Hardware Child Block Incorrectly Connected to Parent System

This vulnerability occurs when a hardware component (IP block) is wired incorrectly to the main system, creating hidden security flaws even if basic functions appear to work.

Definition

What is CWE-1276?

This vulnerability occurs when a hardware component (IP block) is wired incorrectly to the main system, creating hidden security flaws even if basic functions appear to work.
For a system-on-chip (SoC) to operate securely, its internal hardware blocks must communicate with the parent system using the correct control and data signals. An incorrect connection—like linking a reset pin to the wrong system controller—can bypass critical security boundaries. While the device might still boot and run, this miswiring opens a backdoor that attackers can exploit to tamper with sensitive data or operations. Consider a block designed to only clear its data during a full system power cycle. If its reset line is mistakenly connected to a software-controlled debug reset, a privileged process or an attacker gaining software access could trigger an unauthorized reset. This violates the hardware's data integrity guarantees, potentially leaking secrets or corrupting secure state, all while the system seems to function normally from a user's perspective.
Auswirkungen in der Praxis

Real-world CVEs caused by CWE-1276

Bisher sind in MITREs Katalog keine öffentlichen CVE-Referenzen mit dieser CWE verknüpft.

Wie Angreifer es ausnutzen

Angreiferpfad Schritt für Schritt

  1. 1

    Many SoCs use hardware to partition system resources between trusted and un-trusted entities. One example of this concept is the Arm TrustZone, in which the processor and all security-aware IP attempt to isolate resources based on the status of a privilege bit. This privilege bit is part of the input interface in all TrustZone-aware IP. If this privilege bit is accidentally grounded or left unconnected when the IP is instantiated, privilege escalation of all input data may occur.

  2. 2

    In the Verilog code below, the security level input to the TrustZone aware peripheral is correctly driven by an appropriate signal instead of being grounded.

  3. 3

    Here is a code snippet from the Ariane core module in the HACK@DAC'21 Openpiton SoC [REF-1362]. To ensure full functional correctness, developers connect the ports with names. However, in some cases developers forget to connect some of these ports to the desired signals in the parent module. These mistakes by developers can lead to incorrect functional behavior or, in some cases, introduce security vulnerabilities.

  4. 4

    In the above example from HACK@DAC'21, since interrupt signals are not properly connected, the CSR module will fail to send notifications in the event of interrupts. Consequently, critical information in CSR registers that should be flushed or modified in response to an interrupt won't be updated. These vulnerabilities can potentially result in information leakage across various privilege levels.

  5. 5

    To address the aforementioned vulnerability, developers must follow a two-step approach. First, they should ensure that all module signals are properly connected. This can often be facilitated using automated tools, and many simulators and sanitizer tools issue warnings when a signal remains unconnected or floats. Second, it is imperative to validate that the signals connected to a module align with the specifications. In the provided example, the developer should establish the correct connection of interrupt signals from the parent module (Ariane core) to the child module (csr_regfile) [REF-1363].

Verwundbares Codebeispiel

Vulnerable Verilog

Many SoCs use hardware to partition system resources between trusted and un-trusted entities. One example of this concept is the Arm TrustZone, in which the processor and all security-aware IP attempt to isolate resources based on the status of a privilege bit. This privilege bit is part of the input interface in all TrustZone-aware IP. If this privilege bit is accidentally grounded or left unconnected when the IP is instantiated, privilege escalation of all input data may occur.

Verwundbar Verilog 
// IP definition
 module tz_peripheral(clk, reset, data_in, data_in_security_level, ...);

```
   input clk, reset;
   input [31:0] data_in;
   input data_in_security_level;
   ...
 endmodule
 // Instantiation of IP in a parent system
 module soc(...)
   ...
   tz_peripheral u_tz_peripheral(
  	 .clk(clk),
  	 .rst(rst),
  	 .data_in(rdata),
  	 //Copy-and-paste error or typo grounds data_in_security_level (in this example 0=secure, 1=non-secure) effectively promoting all data to "secure")
  	 .data_in_security_level(1'b0),
   );
   ...
 endmodule
Sicheres Codebeispiel

Secure Verilog

In the Verilog code below, the security level input to the TrustZone aware peripheral is correctly driven by an appropriate signal instead of being grounded.

Sicher Verilog 
// Instantiation of IP in a parent system
 module soc(...)

```
   ...
   tz_peripheral u_tz_peripheral(
  	 .clk(clk),
  	 .rst(rst),
  	 .data_in(rdata),
  	 // This port is no longer grounded, but instead driven by the appropriate signal
  	 .data_in_security_level(rdata_security_level),
   );
   ...
 endmodule
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-1276

  • Testing System-level verification may be used to ensure that components are correctly connected and that design security requirements are not violated due to interactions between various IP blocks.
Erkennungssignale

How to detect CWE-1276

SAST High

Führe statische Analyse (SAST) auf der Codebasis aus und suche im Datenfluss nach dem unsicheren Muster.

DAST Moderate

Führe dynamische Application-Security-Tests gegen den Live-Endpoint aus.

Runtime Moderate

Beobachte Runtime-Logs auf ungewöhnliche Exception-Traces, fehlerhafte Eingaben oder Versuche, Autorisierung zu umgehen.

Code review Moderate

Code Review: Markiere jeden neuen Code, der Eingaben von dieser Oberfläche ohne validierte Framework-Helper verarbeitet.

Plexicus Auto-Fix

Plexicus erkennt CWE-1276 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.

Demo anfordern Plexicus kostenlos testen
Häufig gestellte Fragen

Frequently asked questions

Was ist CWE-1276?

This vulnerability occurs when a hardware component (IP block) is wired incorrectly to the main system, creating hidden security flaws even if basic functions appear to work.

Wie gravierend ist CWE-1276?

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-1276 betroffen?

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

Wie kann ich CWE-1276 verhindern?

System-level verification may be used to ensure that components are correctly connected and that design security requirements are not violated due to interactions between various IP blocks.

Wie erkennt und behebt Plexicus CWE-1276?

Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-1276 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-1276?

MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/1276.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.

Verwandte Schwachstellen

Weaknesses related to CWE-1276

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

Bereit, wenn du es bist

Schluss mit dem Bezahlen pro Entwickler.
Schließ den Kreislauf.

Plexicus ist die KI-native ASPM, die scannt, filtert, fixt, pentestet und erklärt — autonom. Unbegrenzte Entwickler, unbegrenzte Repos, Fair-Use-KI-Aktionen. Echter kostenloser Tarif, €269/mo jährlich, wenn du bereit bist.

Kostenlos starten Demo buchen