A fault injection attack matters because an attacker can disturb power, timing, voltage or electromagnetic conditions to force a device into revealing secrets or skipping security checks. This can defeat chips, embedded systems and secure elements even when software is sound. Teams should use tamper resistance, fault detection and validation of critical operations after abnormal conditions.
How fault injection breaks assumptions about “secure by software”
Fault injection matters because it targets a different layer than code correctness. A device may pass normal functional tests and still fail under altered voltage, clock, timing, temperature or electromagnetic conditions, which can expose secrets, bypass checks, or corrupt control flow. That makes it a hardware assurance problem as much as a software security problem.
The practical issue is that many protections assume the platform behaves normally. If an attacker can create a brief disturbance at the right moment, the system may skip an instruction, misread a comparison, or leak intermediate state during cryptographic or access-control operations. Security teams should treat the condition as a test of whether critical operations remain trustworthy outside ideal operating conditions.
For teams reviewing embedded products or secure elements, the key question is not just whether the device works, but whether it fails safely when stressed. That means validating behavior around reset paths, boot checks, debug interfaces, secure storage, and any security decision that depends on a single successful execution path.
Where the attack surface usually lives
Fault injection becomes especially relevant when a device protects high-value secrets or enforces trust at a low level, such as in chips, embedded controllers, authenticators, payment devices, or secure elements. It can undermine protections that look strong on paper because the attack often aims for a tiny timing window rather than a broad software weakness.
Common failure points include cryptographic routines, anti-tamper logic, signature verification, privilege transitions, and integrity checks performed only once. If a check is skipped or a value is perturbed at the wrong moment, the attacker may gain access to protected material or move past a security decision that should have blocked them.
Teams should also note that the strongest exposure is often where hardware and software controls are assumed to back each other up. If one layer is expected to detect a fault while another layer silently trusts the result, the control stack can collapse under a targeted disturbance. This is why validation has to include abnormal-state testing, not just nominal-path testing.
What security teams should verify before they trust the control
Security teams should verify that the product has explicit tamper resistance, fault detection, and recovery behavior for abnormal conditions, not just general hardening. The important evidence is whether the design detects disturbances, refuses to act on corrupted state, and rechecks critical operations after a suspicious event rather than continuing as if nothing happened.
They should also confirm that the supplier or internal engineering team has tested representative fault conditions against the specific security claims being made. A claim that “the chip is secure” is weak unless the test evidence covers the operations that matter most, such as secret handling, key use, and security decision points under induced stress.
Where the product protects credentials or cryptographic material, teams should assess whether a successful fault could expose secrets, weaken authentication, or enable unauthorized privilege changes. In some cases, the right response is not only device replacement or redesign, but rotation of exposed secrets and a review of all systems that trusted the compromised hardware boundary.
Risk and Threat Considerations
Fault injection creates concentrated risk because a short physical disturbance can bypass controls that otherwise appear robust. The threat is not limited to data disclosure, since a successful fault can also disable checks, alter logic, or create a false sense of assurance about the integrity of a security boundary.
Failure mechanism: An attacker applies a precise voltage, clock, timing, thermal, or electromagnetic disturbance during a critical operation, causing skipped instructions, corrupted state, or bypassed verification.
Impact: The device may reveal secrets, accept invalid operations, or continue operating after a security check should have failed, which can lead to compromise of protected chips, embedded systems, and secure elements.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
NIST SP 800-53 Rev 5, CIS Controls v8 and OWASP ASVS set the technical controls, while ISO/IEC 27001:2022 defines the regulatory obligations.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-53 Rev 5 | SI-7 — Software, Firmware, and Information Integrity | Fault injection can corrupt integrity checks and security decisions. |
| SC-30 — Concealment and Misdirection | Tamper and fault-resistance help reduce physical attack leverage on devices. | |
| Recommendation — Add integrity checks and fault-response validation around security-critical operations. Use tamper-resistant design to reduce attacker control over hardware conditions. | ||
| CIS Controls v8 | CIS-12 — Network Infrastructure Management | Embedded and hardware security controls require validated secure configuration and resilience testing. |
| Recommendation — Validate security controls under abnormal operating conditions before deployment. | ||
| OWASP ASVS | V11 — Cryptography | Fault injection often targets cryptographic routines and key handling in devices. |
| Recommendation — Verify cryptographic operations remain protected under abnormal hardware conditions. | ||
| ISO/IEC 27001:2022 | A.8.29 — Security testing in development and acceptance | Security claims about hardware and firmware need testing under adverse conditions. |
| Recommendation — Test security-critical functions under stress and fault conditions before acceptance. | ||
Practitioner Guidance
What to verify: Verify that the vendor or engineering team has tested the exact security path that matters, not just the general device. Pay special attention to boot validation, key use, signature checks, and any one-shot decision that an attacker could target with a timed disturbance.
Decision rule: If a fault could change the outcome of a security decision, require a compensating control such as redundant checking, fault detection, or post-event validation before treating the result as trustworthy. If the operation protects secrets, treat any unexplained abnormal event as a potential exposure event until proven otherwise.
Practitioner takeaway: The main mistake is to equate functional correctness with security assurance, because fault injection attack exploit the gap between “works normally” and “remains trustworthy when stressed.”
Related resources from NHI Mgmt Group
- Guide: Cryptography Basics Guide
- How should security teams use exposure validation to prioritise the controls and attack paths that matter most?
- Why does continuous attack-surface visibility matter for security teams?
- How can security teams detect Mobile Device Fault Injection?
- Why does presentation attack detection matter for security teams?