The best solution to reduce the likelihood of firmware-level attacks and rootkits is to implement measured boot. Measured boot is a hardware-assisted security mechanism that leverages Trusted Platform Module (TPM) and Secure Boot processes. It records cryptographic measurements of each stage of the boot process-from firmware to operating system loaders-and stores them in the TPM. Security software, such as attestation services, can then verify that the system booted into a known, trusted state. If firmware or boot-level code has been tampered with, the measurements will not match expected values, alerting administrators to compromise.
Option A (software integrity checks) validates application-level integrity but does not address firmware rootkits that load before the operating system. Option B (self-encrypting drives) protects data at rest but does not prevent rootkits. Option D (host-based encryption) ensures confidentiality but does not detect or mitigate firmware-level persistence.
Measured boot specifically targets low-level tampering, making it the most relevant control to defend against rootkits and firmware exploits.