Extracting Bitlocker Keys from a TPM

Extracting Bitlocker Keys from a TPM

By default, Microsoft BitLocker protected OS drives can be accessed by sniffing the LPC bus, retrieving the volume master key when it’s returned by the TPM, and using the retrieved VMK to decrypt the protected drive. This post will look at extracting the clear-text key from a TPM chip by sniffing the LPC bus, either with a logic analyzer or a cheap FPGA board. TLDR: You can sniff BitLocker keys in the default config, from either a TPM1.2 or TPM2.0 device, using a dirt cheap FPGA (~$40NZD) and now publicly available code, or with a sufficiently fancy logic analyzer.

Source: pulsesecurity.co.nz