CWE-1429: Missing Security-Relevant Feedback for Unexecuted Operations in Hardware Interface

Description

The product has a hardware interface that silently discards operations in situations for which feedback would be security-relevant, such as the timely detection of failures or attacks.

While some systems intentionally withhold feedback as a security measure, this approach must be strictly controlled to ensure it does not obscure operational failures that require prompt detection and remediation. Without these essential confirmations, failures go undetected, increasing the risk of data loss, security vulnerabilities, and overall system instability. Even when withholding feedback is an intentional part of a security policy designed, for example, to prevent attackers from gleaning sensitive internal details, the absence of expected feedback becomes a critical weakness when it masks operational failures that require prompt detection and remediation. For instance, certain encryption algorithms always return ciphertext regardless of errors to prevent attackers from gaining insight into internal state details. However, if such an algorithm fails to generate the expected ciphertext and provides no error feedback, the system cannot distinguish between a legitimate output and a malfunction. This can lead to undetected cryptographic failures, potentially compromising data security and system reliability. Without proper notification, a critical failure might remain hidden, undermining both the reliability and security of the process. Therefore, this weakness captures issues across various hardware interfaces where operations are discarded without any feedback, error handling, or logging. Such omissions can lead to data loss, security vulnerabilities, and system instability, with potential impacts ranging from minor to catastrophic. For some kinds of hardware products, some errors may be correctly identified and subsequently discarded, and the lack of feedback may have been an intentional design decision. However, this could result in a weakness if system operators or other authorized entities are not provided feedback about security-critical operations or failures that could prevent the operators from detecting and responding to an attack. For example:

Potential Impact

Demonstrative Examples

void interrupt_handler(int irq) {
					  
						if (irq_priority[irq] < current_priority) {
						
						  return;
						
						}
						process_interrupt(irq);
					  
					  }

// Priority threshold for active interrupts
					  int current_priority = 3;
					  // Simulated priority levels for different IRQs
					  int irq_priority[5] = {1, 2, 3, 4, 5};
					  void process_interrupt(int irq) {
					  
						printf("Processing interrupt %d\n", irq);
					  
					  }
					  void interrupt_handler(int irq) {
					  
						if (irq_priority[irq] < current_priority) {
						
						  // Log the dropped interrupt using structured feedback
						  fprintf(stderr, "Warning: Interrupt %d dropped (Priority: %d < Current: %d)\n", 
						  
							irq, irq_priority[irq], current_priority);
						  
						  exit(EXIT_FAILURE);  // Exit with failure status to indicate a critical issue.
						
						}
						process_interrupt(irq);
					  
					  }

If an uncorrectable error occurs, the design does not explicitly
					trigger an alert back to the execution core.

Modify the design so that any uncorrectable error triggers an alert
					back to the execution core and gets handled before the core can
					consume the data read/written through the corrupted transactions.
					Update design access control policies to ensure that alerts sent to
					execution core on uncorrectable errors cannot be disabled or masked by
					untrusted software/firmware.

Mitigations & Prevention

Detection Methods

• Automated Static Analysis - Source Code High — Scans code for missing error handling or feedback mechanisms.
• Manual Static Analysis - Source Code Moderate — Experts manually inspect the code for unhandled operations.

Real-World CVE Examples

Related Weaknesses