TL;DR
Yes, BIOS firmware can log keyboard input. It’s rare but serious. Detecting it is hard, as standard security tools often don’t scan the BIOS. Prevention involves secure boot, regular updates, and careful attention to system integrity.
Understanding the Threat
Your computer’s Basic Input/Output System (BIOS) or Unified Extensible Firmware Interface (UEFI) is the first software that runs when you power on your machine. Because it has such low-level access, malicious code embedded in the BIOS can intercept keyboard input before the operating system even loads – effectively creating a keylogger that’s very difficult to detect.
Detecting BIOS Keyloggers
- Check Boot Order: Look for unusual entries in your boot order. A rogue BIOS might try to load from an unexpected source.
- Access the BIOS setup (usually by pressing Del, F2, F12, or Esc during startup – check your motherboard manual).
- Examine the Boot Order/Boot Priority settings.
- If you see unfamiliar devices listed, investigate further.
- BIOS Update History: Many BIOS setups log update history. Check if there are any unexpected or unauthorized updates.
- Within the BIOS setup, look for a section called “Update Log”, “Flash History” or similar.
- Verify that all listed updates were performed by you or your trusted IT support.
- UEFI Secure Boot Status: Ensure Secure Boot is enabled.
- In the BIOS setup, find the “Secure Boot” option (usually under Boot or Security settings).
- It should be set to ‘Enabled’. If it’s disabled, re-enable it.
- Hardware Inspection: Visually inspect your motherboard for any signs of tampering.
- This is best done by a qualified technician. Look for added chips or modifications to the BIOS chip itself.
- Rootkit Scanners (Limited Effectiveness): While not specifically designed for BIOS keyloggers, some advanced rootkit scanners might detect malicious code loaded at a low level.
- Run reputable anti-malware software with rootkit scanning capabilities. Examples include Malwarebytes and Sophos.
- Be aware that these tools have limited success against sophisticated BIOS malware.
- Memory Dump Analysis (Advanced): This requires significant technical expertise.
- You can attempt to dump the contents of your BIOS chip and analyze it for malicious code. Tools like UEFITool can help with this, but it’s a complex process.
Preventing BIOS Keyloggers
- Enable Secure Boot: This is the most important step.
- Secure Boot verifies that only trusted software loads during startup, preventing malicious code from running in the BIOS.
- Regularly Update Your BIOS/UEFI Firmware: Manufacturers often release updates to patch security vulnerabilities.
- Download updates directly from your motherboard manufacturer’s website. Do not use third-party update tools.
- Follow the manufacturer’s instructions carefully during the update process – a failed update can brick your motherboard.
- Physical Security: Prevent unauthorized physical access to your computer.
- A determined attacker could physically modify the BIOS chip.
- BIOS Password Protection: Set a strong password in the BIOS setup.
- This prevents unauthorized changes to the BIOS settings, including boot order and Secure Boot configuration.
- TPM (Trusted Platform Module): Use a TPM chip if your motherboard supports it.
- A TPM provides hardware-based security features that can help protect against BIOS attacks.
- Be Careful with Custom Firmware: Avoid flashing custom or modified firmware unless you fully understand the risks.
- Custom firmware may contain hidden malware.
Command Examples (for advanced users)
These commands are for informational purposes only and require a good understanding of your system.
# Check Secure Boot status (Linux example - may vary by distribution)
mokutil --sb-state