CWE-1304: Improperly Preserved Integrity of Hardware Configuration State During a Power Save/Restore Operation

Inside the IP, incorporate integrity checking
on the configuration state via a cryptographic
hash. The hash can be protected inside the IP such as
by storing it in internal registers which never lose
power. Before powering down, the IP performs a hash of
the configuration and saves it in these persistent
registers. Upon restore, the IP performs a hash of the
saved configuration and compares it with the
saved hash. If they do not match, then the IP should
not trust the configuration.

Outside the IP, incorporate integrity checking
of the configuration state via a trusted agent. Before
powering down, the trusted agent performs a hash of the
configuration and saves the hash in persistent storage.
Upon restore, the IP requests the trusted agent
validate its current configuration. If the
configuration hash is invalid, then the IP should not
trust the configuration.

Outside the IP, incorporate a protected
environment that prevents undetected modification of
the configuration state by untrusted agents. Before
powering down, a trusted agent saves the IP's
configuration state in this protected location that
only it is privileged to. Upon restore, the trusted
agent loads the saved state into the IP.