Secure Boot Bypass Risk Threatens Nearly 200,000 Linux Framework Laptops

Roughly 200,000 Linux-based Framework laptops shipped with a signed UEFI shell command (mm) that can be abused to bypass Secure Boot protections -- allowing attackers to load persistent bootkits like BlackLotus or HybridPetya. Framework has begun patching affected models, though some fixes and DBX updates are still pending. BleepingComputer reports: According to firmware security company Eclypsium, the problem stems from including a 'memory modify' (mm) command in legitimately signed UEFI shells that Framework shipped with its systems. The command provides direct read/write access to system memory and is intended for low-level diagnostics and firmware debugging. However, it can also be leveraged to break the Secure Boot trust chain by targeting the gSecurity2 variable, a critical component in the process of verifying the signatures of UEFI modules.

The mm command can be abused to overwrite gSecurity2 with NULL, effectively disabling signature verification. 'This command writes zeros to the memory location containing the security handler pointer, effectively disabling signature verification for all subsequent module loads.' The researchers also note that the attack can be automated via startup scripts to persist across reboots.

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