Scans code for missing error handling or feedback mechanisms.
CWE-1429 Base Incomplete
Missing Security-Relevant Feedback for Unexecuted Operations in Hardware Interface
This vulnerability occurs when a hardware interface discards operations without providing any security-relevant feedback, such as error notifications or logs. This silence prevents the timely…
Definition
What is CWE-1429?
This vulnerability occurs when a hardware interface discards operations without providing any security-relevant feedback, such as error notifications or logs. This silence prevents the timely detection of critical failures or active attacks, leaving systems vulnerable to undetected compromise.
Hardware interfaces that silently discard operations create a dangerous blind spot. While suppressing feedback can sometimes be a legitimate security tactic—like preventing attackers from learning internal system details—it becomes a major weakness when it also hides operational failures. Without proper error handling or logging, cryptographic failures, unauthorized access attempts, or system malfunctions can go completely unnoticed, leading to data loss, instability, and hidden security breaches.
For developers, the challenge is balancing security through obscurity with the operational need for actionable diagnostics. You must implement controlled feedback mechanisms—like secure internal logging or privileged error channels—that alert authorized systems without leaking sensitive data to potential attackers. Managing these feedback loops across complex hardware/software stacks is difficult; an ASPM like Plexicus can help by correlating system behaviors to identify where critical operations are failing silently and suggesting targeted remediations.
Real-world impact
Real-world CVEs caused by CWE-1429
-
Open source silicon root of trust (RoT) product does not immediately report when an integrity check fails for memory requests, causing the product to accept and continue processing data [REF-1468]
How attackers exploit it
Step-by-step attacker path
- 1
This code creates an interrupt handler. If the interrupt's priority is lower than the currently active one, the interrupt is discarded without any feedback, perhaps due to resource constraints.
- 2
The omission of feedback for the dropped lower-priority interrupt can cause developers to misinterpret the state of the system, leading to incorrect assumptions and potential system failures, such as missed sensor readings. Attackers might leverage this lack of visibility to induce conditions that lead to timing side-channels. For example, an attacker could intentionally flood the system with high-priority interrupts, forcing the system to discard lower-priority interrupts consistently. If these discarded interrupts correspond to processes executing critical security functions (e.g., cryptographic key handling), an attacker might measure system timing variations to infer when and how those functions are executing. This creates a timing side channel that could be used to extract sensitive information. Moreover, since these lower-priority interrupts are not reported, the system remains unaware that critical tasks such as sensor data collection or maintenance routines, are being starved of execution. Over time, this can lead to functional failures or watchdog time resets in real-time systems. One way to address this problem could be to use structured logging to provide visibility into discarded interrupts. This allows administrators, developers, or other authorized entities to track missed interrupts and optimize the system.
- 3
Consider a SoC design with these component IPs: IP 1. Execution Core IP 2 SoC Fabric (NoC, tile etc. ) IP 3 Memory Controller External/ internal memory. The Core executes operations that trigger transactions that traverse the HW fabric links to read/write to the final memory module. There can be unexpected errors in each link. For adding reliability and redundance, features like ECCs are used in these transactions. Error correction capabilities have to define how many error bits can be detected and which errors can be corrected, and which are uncorrectable errors. In design, often the severity level and response on different errors is allowed to be configured by system firmware modules like BIOS.
- 4
For system security, if an uncorrectable error occurs but is not reported to the execution core and handled before the core attempts to consume the data that is read/written through the corrupted transactions, then this could enable silent data corruption (SDC) attacks. In the case of confidential compute technologies where system firmware is not a trusted component, error handling controls can be misconfigured to trigger this weakness and attack the assets protected by confidential compute.
Vulnerable code example
Vulnerable C
This code creates an interrupt handler. If the interrupt's priority is lower than the currently active one, the interrupt is discarded without any feedback, perhaps due to resource constraints.
void interrupt_handler(int irq) {
```
if (irq_priority[irq] < current_priority) {
return;
}
process_interrupt(irq);
} Secure code example
Secure C
The omission of feedback for the dropped lower-priority interrupt can cause developers to misinterpret the state of the system, leading to incorrect assumptions and potential system failures, such as missed sensor readings. Attackers might leverage this lack of visibility to induce conditions that lead to timing side-channels. For example, an attacker could intentionally flood the system with high-priority interrupts, forcing the system to discard lower-priority interrupts consistently. If these discarded interrupts correspond to processes executing critical security functions (e.g., cryptographic key handling), an attacker might measure system timing variations to infer when and how those functions are executing. This creates a timing side channel that could be used to extract sensitive information. Moreover, since these lower-priority interrupts are not reported, the system remains unaware that critical tasks such as sensor data collection or maintenance routines, are being starved of execution. Over time, this can lead to functional failures or watchdog time resets in real-time systems. One way to address this problem could be to use structured logging to provide visibility into discarded interrupts. This allows administrators, developers, or other authorized entities to track missed interrupts and optimize the system.
// 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);
} What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist
How to prevent CWE-1429
- Architecture and Design Incorporate logging and feedback mechanisms during the design phase to ensure proper handling of discarded operations.
- Implementation Developers should ensure that every critical operation includes proper logging or error feedback mechanisms.
Detection signals
How to detect CWE-1429
Experts manually inspect the code for unhandled operations.
Plexicus auto-detects CWE-1429 and opens a fix PR in under 60 seconds.
Codex Remedium scans every commit, identifies this exact weakness, and ships a reviewer-ready pull request with the patch. No tickets. No hand-offs.
Frequently asked questions What is CWE-1429?
How serious is CWE-1429?
What languages or platforms are affected by CWE-1429?
How can I prevent CWE-1429?
How does Plexicus detect and fix CWE-1429?
Where can I learn more about CWE-1429?
Frequently asked questions
What is CWE-1429?
This vulnerability occurs when a hardware interface discards operations without providing any security-relevant feedback, such as error notifications or logs. This silence prevents the timely detection of critical failures or active attacks, leaving systems vulnerable to undetected compromise.
How serious is CWE-1429?
MITRE has not published a likelihood-of-exploit rating for this weakness. Treat it as medium-impact until your threat model proves otherwise.
What languages or platforms are affected by CWE-1429?
MITRE lists the following affected platforms: C, C++, Verilog, Hardware Description Language, ARM, x86, Embedded, Security Hardware.
How can I prevent CWE-1429?
Incorporate logging and feedback mechanisms during the design phase to ensure proper handling of discarded operations. Developers should ensure that every critical operation includes proper logging or error feedback mechanisms.
How does Plexicus detect and fix CWE-1429?
Plexicus's SAST engine matches the data-flow signature for CWE-1429 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.
Where can I learn more about CWE-1429?
MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/1429.html. You can also reference OWASP and NIST documentation for adjacent guidance.
Related weaknesses
Weaknesses related to CWE-1429
CWE-223 Parent
Omission of Security-relevant Information
This vulnerability occurs when an application fails to capture or present crucial security-related details, such as the origin of a…
CWE-778 Sibling
Insufficient Logging
This weakness occurs when an application fails to properly record important security events or captures them with insufficient detail,…
CWE-392 Peer
Missing Report of Error Condition
This vulnerability occurs when a system fails to properly signal that an error has happened. Instead of returning a clear error code,…
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