BIOS firmware is the foundational software that initializes hardware and launches the operating system. If compromised, an attacker can replace it with a rogue OS, gaining full control of the system while bypassing traditional security measures. This allows them to establish deep persistence, execute malicious code, and render OS-level security and antivirus protections completely ineffective—even before the legitimate operating system loads.
In fact, according to an HP Wolf Security study, more than 80% of IT decision-makers worry about firmware security, recognizing that BIOS-level attacks are particularly stealthy and difficult to detect. In this context, quick action is crucial. If your BIOS firmware has been breached, following the right steps can mitigate damage, restore integrity, and prevent future attacks.
Understanding BIOS Firmware Threats
What is BIOS, and Why Is It Critical for Security?
BIOS firmware is embedded on the motherboard, and it initializes the hardware before launching the operating system. As the first code executed at startup, it plays a foundational (and critical) role in system integrity. A compromised BIOS can allow attackers to:
- Bypass Secure Boot – Secure Boot ensures that only firmware that is trusted by the OEM boots when the device starts.
- Persist through reboots and OS reinstalls – Malware can embed itself at a low level, surviving full disk wipes.
- Bypass security tools – Since BIOS operates below the OS, traditional antivirus solutions cannot even detect, let alone remove threats.
- Gain deep system control – Attackers can manipulate hardware settings, disable security features, or inject malicious code.
This creates a perfect storm where hackers can assume control over your endpoint (or entire fleet) of them without you even knowing. And once control is granted, they have “the keys to the kingdom” to do as they please.
How BIOS Attacks Work
BIOS-level threats are particularly dangerous due to their stealth and persistence. Attackers exploit vulnerabilities in outdated firmware, insecure configurations, or unpatched security flaws. Common techniques include:
- Firmware tampering – Modifying the BIOS to introduce malicious code.
- Exploiting misconfigurations – Disabling Secure Boot or injecting unsigned firmware updates.
- Hardware-based attacks – Using physical access or supply chain compromise to introduce backdoors.
Notable BIOS-Level Attacks
And if you think that compromises at the BIOS firmware level are merely fantasy – think again. There have been several recent, notable attacks which caused industry-wide recognition due to the severity of the breach, and the means of attack. These include:
- Black Lotus – A sophisticated UEFI bootkit that can bypass Secure Boot and establish deep persistence.
- LogoFAIL – A firmware vulnerability that allows attackers to inject malware via corrupted logo images during boot.
Book your FirmGuard trial today and discover the firmware vulnerabilities lurking in your endpoints.
Signs That Your BIOS Has Been Compromised
A BIOS breach often manifests through subtle system anomalies. If you notice any of the following, your firmware integrity may be at risk, and you should immediately seek to isolate the potentially affected system for further troubleshooting:
- Unexplained system reboots or crashes – Persistent instability with no clear cause.
- BIOS settings changing without user input – Security settings disabled or altered unexpectedly. For example, the Secure Boot setting is inexplicably turned off.
- Security alerts or integrity check failures – Firmware validation tools flagging inconsistencies.
- Malware persistence after OS reinstall – Malicious code reappears even after a fresh OS installation.
- Slow boot times or freezing during startup – The system hangs or experiences abnormal delays at boot.
These are some of the more common indicators, but as attackers continuously evolve their means of attack, it’s critical to stay vigilant to abnormalities. This will help to ensure the safety of your BIOS firmware and system in general. Now that we’ve covered some signs of a breach, the next question that must be asked is what should you do if you suspect a breach?
Immediate Steps to Take After a Suspected BIOS Breach
Step 1: Isolate the Affected System
- Disconnect from the network immediately – This prevents malware from spreading laterally.
- Power down the machine – If the breach is active, shutting down halts unauthorized processes.
Step 2: Verify the Integrity of BIOS Firmware
- Use vendor-provided tools – Most hardware manufacturers offer utilities to verify firmware integrity.
- Check against known firmware hashes – Compare with a clean, trusted version from the manufacturer.
- Monitor firmware with specialized tools – Endpoint security solutions, such as FirmGuard, can detect unauthorized changes and anomalies.
Step 3: Securely Restore BIOS Firmware
- Reflash BIOS using a clean, trusted source – Obtain the latest firmware directly from the manufacturer’s website.
- Enable secure update mechanisms – Ensure updates are digitally signed and verified.
- Run a post-flash integrity check – Confirm the reinstallation was successful and no malicious changes persist.
Step 4: Investigate and Assess Further Impact
- Check for persistence mechanisms – Attackers may leave hidden backdoors within hardware components.
- Scan other networked devices – If the breach was part of a larger attack, other systems may be compromised.
- Review security logs and alerts – Look for unusual activity that may indicate further compromise.
Strengthening BIOS Security to Prevent Future Breaches
Now that you have taken the necessary steps to resolve the issue, it is important to stay ahead of BIOS firmware security, so issues don’t reappear. As the saying goes, an ounce of prevention is worth a pound of cure. Strengthening BIOS security minimizes the risk of future attacks – here are some steps you should consider:
- Enable BIOS protection measures – Secure Boot, Trusted Platform Module (TPM), and BIOS passwords help prevent unauthorized changes.
- Implement endpoint protection with firmware security – Solutions that monitor BIOS integrity can detect early signs of tampering.
- Regularly update BIOS firmware – Firmware updates contain security patches which fix vulnerabilities that attackers exploit. So it is important to continuously monitor for firmware updates.
These measures, combined with robust monitoring, create a strong defense against BIOS-level threats.
How FirmGuard Can Help
Protecting BIOS firmware requires specialized expertise and tools. FirmGuard offers solutions that help organizations secure, configure, and update BIOS firmware. The FirmGuard platform supports critical BIOS security use cases, including:
- Remote BIOS configuration – FirmGuard allows your (and/or your team) to modify BIOS settings remotely, meaning they no longer need to travel on site to access the endpoint – this ensures greater operational efficiency, while reducing the time and costs associated with on-site travel.
- Remote BIOS update – FirmGuard provides a centralized, secure and standardized way to make UEFI BIOS firmware updates across a heterogeneous mix of endpoints, all with minimal involvement from IT staff.
- Endpoint disk erasure – Securely erasing data on an endpoint is critical to ensure compliance with regulatory standards – however it was traditionally done in a physical manner (crushing the endpoint etc.). FirmGuard enables you to securely erase endpoints, even to a military standard, while also providing a Certificate of Erasure (CoE) and ensuring that you stay compliant with relevant ISO and NIST standards.
It’s Only a Matter of Time
A BIOS breach is one of the most severe security threats an organization can face. The persistence and stealth of these attacks make quick action essential. By isolating compromised systems, verifying firmware integrity, and reinforcing BIOS security, you can mitigate risks and prevent future intrusions.
Staying ahead of BIOS threats requires continuous monitoring and proactive security measures. Investing in the right tools ensures that your firmware remains protected from evolving attacks. Book your FirmGuard demo today and learn how to stop firmware breaches, before they happen.
