Intel is investigating a leak of private keys allegedly used by the Intel Boot Guard security feature that could potentially affect its ability to block the installation of malicious firmware on MSI devices. The leak was allegedly due to the attack by the Money Message extortion gang in March, where it claimed to have stolen 1.5TB of data from MSI. The gang then demanded a $4 million ransom, and after not being paid, started leaking the data.
Recently, they began leaking the source code for firmware used by MSI’s motherboards. The leaked source code contains image signing private keys for 57 MSI products and Intel Boot Guard private keys for 116 MSI products, impacting the security of MSI devices using 11th Tiger Lake, 12th Adler Lake, and 13th Raptor Lake CPUs.
Intel Boot Guard is a critical security feature used to prevent the loading of malicious firmware, known as UEFI bootkits, and is designed to meet Windows UEFI Secure Boot requirements.
The feature is built into modern Intel hardware and works by verifying if a firmware image is signed using a legitimate private signing key, using an embedded public key built into the Intel hardware. If the firmware can be verified as legitimately signed, Intel Boot Guard will allow it to be loaded on the device.
However, if the signature fails, the firmware will not be allowed to load. Unfortunately, the leaked private keys will allow a potential attacker to sign the modified firmware for the device, so it would pass Intel Boot Guard’s verification, rendering the technology completely ineffective.
The leak of Intel Boot Guard private keys is a direct threat to MSI customers and the entire Intel ecosystem, as attackers can craft malicious firmware updates and deliver them through a normal BIOS update process with MSI update tools.
Although most threat actors will not be able to use these keys, skilled attackers have used malicious firmware in attacks before. The public keys used to verify firmware signed using the leaked keys are believed to be built into Intel hardware, and if they cannot be modified, the security feature will no longer be trustworthy on devices using those leaked keys. The leak may have caused Intel Boot Guard not to be effective on devices using MSI products with the affected CPUs.
