Hardware fault induction attacks

Hardware fault induction attacks are a class of side-channel attacks where intentional faults are introduced into the hardware to disrupt its normal operation. These faults can cause errors in computation, bypass security mechanisms, or expose sensitive data. Fault induction attacks can target various aspects of hardware, such as power supply, clock signals, temperature, and physical integrity.

Types of Hardware Fault Induction Attacks

1. Voltage Fault Injection (Voltage Glitching)
   • Description: The attacker manipulates the power supply voltage to induce faults. By suddenly dropping or spiking the voltage, the system can be forced into a fault state.
   • Impact: Skipping instructions, data corruption, bypassing security checks.
2. Clock Fault Injection (Clock Glitching)
   • Description: Involves injecting glitches into the clock signal. These high-frequency pulses disrupt the timing of operations.
   • Impact: Causes timing violations, unintended execution of instructions, bypassing secure operations.
3. Temperature Fault Injection
   • Description: The attacker manipulates the operating temperature of the device. This can be done by heating or cooling the device beyond its normal operating range.
   • Impact: Alters the behavior of transistors, potentially leading to data corruption or security bypass.
4. Optical Fault Injection (Laser Fault Injection)
   • Description: A focused laser is used to disrupt the operation of specific areas of the chip by causing localized heating or ionization.
   • Impact: Selectively corrupts data or instructions, potentially exposing sensitive information or bypassing security mechanisms.
5. Electromagnetic Fault Injection (EMFI)
   • Description: The device is exposed to a strong electromagnetic field, which induces faults in its operation.
   • Impact: Disrupts normal processing, potentially leading to security breaches or data leakage.
6. Mechanical Fault Injection
   • Description: Physical stress, such as bending or applying pressure, is applied to the chip to induce faults.
   • Impact: Causes mechanical disruptions that can lead to logical errors or physical damage.

Steps to Perform a Hardware Fault Induction Attack

1. Identify the Target
   • Choose a device or system to target, such as a microcontroller, smart card, or embedded system.
   • Study the architecture and understand critical operations and security features.
2. Set Up Fault Injection Equipment
   • Voltage Glitching: Use a programmable power supply or glitch generator.
   • Clock Glitching: Employ a clock signal injector or pulse generator.
   • Temperature Control: Use heating elements or cooling sprays.
   • Optical Equipment: Set up a laser with precise targeting capability.
   • Electromagnetic Field Generator: Utilize an EM field generator or coil.
   • Mechanical Tools: Apply controlled physical stress using precision tools.
3. Inject Faults
   • Introduce faults during critical operations, such as authentication or cryptographic processing.
   • Carefully control the timing and intensity of the fault to maximize the likelihood of inducing a useful error without crashing the system.
4. Observe and Analyze
   • Monitor the device’s response to the induced faults.
   • Look for anomalies such as skipped instructions, data leaks, or security bypasses.
   • Use debugging tools, logic analyzers, or oscilloscopes to capture detailed information about the fault response.
5. Exploit the Fault
   • If the fault leads to useful anomalies (e.g., bypassed security checks or exposed data), use this information to further the attack.
   • Iterate the process, refining the fault injection parameters to improve the effectiveness of the attack.

Applications of Hardware Fault Induction Attacks

1. Breaking Cryptographic Implementations
   • Faults can be used to disrupt cryptographic operations, making it possible to deduce secret keys or decrypt data.
2. Bypassing Authentication Mechanisms
   • By inducing faults during authentication checks, attackers can bypass PINs, passwords, or other security controls.
3. Reverse Engineering and Debugging
   • Fault induction can help in understanding proprietary algorithms or security mechanisms by forcing the system to behave abnormally.
4. Data Extraction
   • Faults can lead to the leakage of sensitive data, such as encryption keys or confidential user information.

Mitigation Techniques

1. Hardware Countermeasures
   • Redundant Circuitry: Use of redundant hardware to detect and correct faults.
   • Fault Detection Circuits: Incorporate circuits that detect abnormal operating conditions and reset the system.
2. Software Countermeasures
   • Error Detection and Correction (EDC): Implement software routines that detect and correct errors caused by faults.
   • Randomized Execution: Introduce randomness in execution timing to make fault injection harder.
3. System-Level Defenses
   • Secure Boot: Validate the integrity of firmware and software before execution.
   • Tamper Detection: Use sensors to detect physical tampering or abnormal environmental conditions.