Exploiting signed bootloaders to circumvent UEFI Secure Boot
Summary
The article analyzes how signed bootloaders and UEFI Secure Boot can be bypassed using PreLoader/shim and modified GRUB2, detailing how keys or hashes can be enrolled to trust untrusted .efi binaries. It discusses practical disk images that enable booting unsigned code with Secure Boot enabled, and warns about potential misuse and defensive implications.