What is Fault injection?

Fault injection is an attack and testing technique where deliberate errors are introduced into a system to observe how it behaves under abnormal conditions. In cybersecurity, attackers use it to bypass controls, extract secrets, alter program flow, or trigger insecure failure states.

Faults can be physical, software-based, or environmental. The goal is not simply to crash a system, but to make it fail in a useful way for the attacker.

How Fault injection works

A fault injection attack targets the assumptions a device, application, or process makes while running. If a security check expects a stable processor, memory state, voltage level, clock signal, or input sequence, a precisely timed fault can disrupt that check.

For example, an attacker may try to skip an authentication step, corrupt a cryptographic calculation, or force a device to reveal protected data. In software environments, fault injection may involve malformed inputs, API failures, memory corruption, or simulated service outages.

The technique is also used defensively. Security teams and developers inject controlled faults to test whether systems recover safely, protect sensitive data, and fail closed instead of failing open.

Common types of Fault injection

It can take several forms depending on the target and attacker capability.

• Hardware: Uses voltage glitches, clock glitches, electromagnetic pulses, lasers, or temperature changes to disturb device behavior.
• Software: Introduces unexpected inputs, memory faults, dependency failures, or exception conditions into an application.
• Protocol: Sends malformed or out-of-order network messages to test how a protocol implementation responds.
• Chaos-style: Simulates outages, latency, or component failures to validate system resilience.

In adversary techniques, hardware and software fault injection are especially relevant because they can undermine security controls that appear sound under normal operating conditions.

Why Fault injection matters in cybersecurity

It matters because many security controls assume predictable execution. If attackers can disturb that execution, they may bypass checks without needing valid credentials or a traditional software exploit.

Embedded systems, payment devices, IoT hardware, mobile devices, and secure boot chains are common areas of concern. However, enterprise software can also be affected when applications handle dependency failures, corrupted data, or race conditions poorly.

For business security teams, the practical question is whether critical systems handle failure safely. A strong design should verify sensitive operations, validate outputs, log abnormal behavior, and avoid exposing secrets when something goes wrong.

How organizations reduce Fault injection risk

Organizations can reduce risk by combining secure design, testing, monitoring, and device management. Hardware-backed protections such as secure elements, tamper resistance, redundancy, and fault detection can make physical attacks harder. Software teams can add input validation, defensive error handling, retry limits, integrity checks, and independent verification of critical decisions.

For managed endpoints and mobile devices, tools such as Hexnode can support broader protection by enforcing security policies, controlling device configurations, restricting risky states, and helping IT teams respond when devices show signs of compromise.

Fault injection cannot always be eliminated, but its impact can be reduced when systems are built to distrust abnormal states and recover securely.