BIOS and Bootloaders in the Crosshairs: Growing Firmware Threats

Hackers are increasingly targeting the early stages of a system’s startup sequence—specifically BIOS, UEFI, and bootloaders, according to Cybernews. These pre-OS environments are becoming attractive entry points because they allow attackers to bypass conventional operating system-level defenses and gain long-lasting control over a device. According to researchers at Eclypsium, such firmware threats are often missed by traditional security solutions, giving attackers a stealthy and persistent foothold.

Bootkits like BlackLotus, BootHole, and EFILock illustrate how modern attacks exploit vulnerabilities in boot components—even those protected by Secure Boot. By embedding themselves in firmware or replacing legitimate bootloaders, attackers can survive OS reinstalls and even some hardware replacements. This level of persistence makes remediation extremely difficult and raises the stakes for enterprise defenders and OEMs alike.

Attack vectors typically involve compromised storage, network connections, or console inputs during the boot process. Once in, malicious code can execute before any security software starts, effectively seizing control over the system. In some cases, attackers exploit misconfigured or outdated signature databases—such as DBX and SBAT policies—allowing revoked or unsigned binaries to run unnoticed. Downgrade attacks further complicate mitigation efforts by exploiting older, vulnerable firmware versions.

To counter this growing threat, organizations must move beyond OS-level protections. Eclypsium recommends enforcing Secure Boot policies, keeping signature databases up to date, and monitoring boot behavior for anomalies.