If you've got time (and a deep understanding of solid state electronics) then take a look at this demonstration of a hardware Trojan at the sub-gate level.http://people.umass.edu/gbecker/BeckerChes13.pdf
TL;DR They can compromise a chip design (verified by an independent security company) which is NIST SP800-90, FIPS 140-2, and ANSI X9.82 compliant. They can modify the digital post-processing of the design at the sub-transistor level to compromise the security of keys generated with the RNG.
Their Trojan is capable of reducing the security of the produced random number from 128 bits to n bits, where n can be chosen. Despite these changes, the modified Trojan RNG passes not only the Built-In-Self-Test (BIST) but also generates random numbers that pass the NIST test suite for random numbers.
TL;DR for the TL;DR
All crypto hardware could be compromised. Start getting your random numbers from the background radiation of the universe.