DetectTpmSpoofing

Small WDM/WDF-style kernel driver that checks whether TPM 2.0 responses on a machine have been tampered with, i.e. spoofed by a driver that hooks IRP_MJ_DEVICE_CONTROL / DeviceIoControl on \Driver\TPM.

Why

Some cheats/spoofers install a filter or hook on the TPM device stack so that TPM2_ReadPublic (and similar commands) return a forged public key/EK instead of the real one, letting them fake hardware identity to anti-cheat or attestation checks. The forged data only shows up on the IOCTL path, because the hook sits between the caller and the real TPM.

How it works

The driver gets the same TPM2_ReadPublic result two different ways and compares them:

1. HashTpmIoctl — opens \??\TPM directly and sends a raw TPM2_ReadPublic command via ZwDeviceIoControlFile, exactly like a userland caller would through DeviceIoControl. This is the path a hook would intercept.
2. HashTpmCached — walks the TPM.sys driver object, follows its WDF device context to the internal TPM_STACK / resource manager structures, and reads the cached response buffer the TPM driver already stored for handle 0x81010001 (the EK). This bypasses the IOCTL path entirely, so a hook on DeviceIoControl has no way to touch it.

Both responses get parsed (IsReadPublicRSA2048) and hashed with a small FNV-1a implementation. If both hashes come back non-zero, the driver logs whether they match. If a hook is spoofing the IOCTL response, the two hashes will differ — the IOCTL path shows the fake key, the cached path still holds the real one.

Note: the offsets into TPM_STACK / TPM_RESMGR are reverse engineered from TPM.sys and will need to be re-checked against the target Windows build if they stop matching. The WDF context type-info (_WDF_TpmStack_TYPE_INFO) is located by walking TPM.sys's PE section table for .data and assuming it sits at the start of that section — also hacky, same caveat applies.

Files

• src/Driver.cpp — the driver itself (entry point, IOCTL path, cached-buffer path, comparison).
• src/tpm12.h, src/tpm20.h — TCG TPM 1.2/2.0 spec structures and constants used to build/parse the ReadPublic command.

Building

Requires the WDK and Ninja/cl.exe (see CMakePresets.json).

cmake --preset x64-debug
cmake --build --preset x64-debug

Sign the resulting driver with