Performing a voltage or clock glitching attack requires specialized equipment, a thorough understanding of the target system, and precise timing. Here’s a step-by-step guide on how these attacks are typically carried out:
1. Understand the Target System
- Study the Device: Obtain detailed documentation of the target system, such as datasheets, user manuals, and firmware analysis.
- Identify Critical Operations: Determine which parts of the system’s operation are critical for security, such as authentication checks, cryptographic processes, or firmware validation.
2. Set Up the Necessary Equipment
- Voltage Glitching Setup:
- Power Supply: Use a programmable power supply or a glitch generator that can produce rapid changes in voltage.
- Probe Connections: Connect probes to the power supply lines of the target device.
- Control Software: Utilize software to control the glitch timing and duration.
- Clock Glitching Setup:
- Oscilloscope: Use an oscilloscope to observe the device’s normal clock signal.
- Clock Injector: Use a device capable of injecting high-frequency pulses into the clock line.
- Signal Generators: Generate controlled clock pulses for precise glitching.
3. Determine Timing and Parameters
- Timing Analysis: Identify when critical operations occur. This is typically done by monitoring the power or clock lines using an oscilloscope or logic analyzer.
- Glitch Parameters: Set the duration, amplitude, and frequency of the glitches. These parameters are crucial as they must be precise enough to induce faults without causing a complete system crash.
4. Inject the Glitch
- Voltage Glitching:
- Apply the glitch during the execution of critical code, such as password checks or cryptographic operations.
- Gradually adjust the timing and intensity of the glitch to find the most effective configuration.
- Clock Glitching:
- Inject high-frequency pulses or alter the clock signal at critical moments.
- Monitor the system’s response to ensure that the glitches are causing the desired faults.
5. Observe the Effects
- Behavior Analysis: Look for signs of unintended behavior, such as skipped instructions, incorrect data processing, or bypassed security checks.
- Data Extraction: If the attack is successful, it may lead to the exposure of sensitive information or the bypassing of authentication mechanisms.
6. Refine and Repeat
- Adjust Parameters: Based on the initial results, fine-tune the glitch parameters to increase the likelihood of success.
- Automate the Process: Use scripts or automation tools to repeatedly inject glitches and observe responses, allowing for more extensive testing and refinement.
Tools Required
- Glitch Generators: Devices like ChipWhisperer or custom-built glitchers.
- Oscilloscope: For monitoring power and clock lines.
- Power Supply: Programmable to allow for precise voltage control.
- Logic Analyzer: To analyze and debug the system’s response to glitches.
- Signal Generators: For clock signal manipulation.