This quote from the recently published “Blacksmith” work (See:  https://lnkd.in/ggwWeMyX) is succinct, impactful, and contains an explicit warning :

“Concluding, our work confirms that the DRAM vendors’ claims about Rowhammer protections are false and lure you into a false sense of security. All currently deployed mitigations are insufficient to fully protect against Rowhammer. Our novel patterns show that attackers can more easily exploit systems than previously assumed.“

Industry as a whole needs to pay attention to the apparent trend here. Beginning with the original basic rowhammer discovery circa 2014, to work such as Google’s recent “Half Double” exploit publication (See: https://lnkd.in/guAuy9GR) and now the “Blacksmith” paper, one could argue that at least in appearance (if not fact) the level of vulnerability is actually increasing over time.

One can easily be sceptical regarding continued DRAM scaling unless there are some fundamental changes in the cell materials and/or structure in the future. As it stand now, there is little to no (or negative?) $/bit advantage for the 1-ish nm cell pitch improvements of late. Amortization of EUV equipment, cost of multi-patterning, and TCO killers such as the end user paying for on-die ECC bits, and relaxation of core timing parameters result in little value to the end user. Assuming rowhammer behavior may be more difficult to mitigate with tighter cell pitches, is this simply another example of reduced end customer value as a byproduct of enabling more DRAM Mfg revenue per wafer? (Side note: Please see https://lnkd.in/gumJCiVy by Andrew Walker et al for a detailed description of the basic phenomena.)

One last thought is regarding the word “mitigation”. The “Blacksmith” paper references mitigations such as TRR, and other papers refer to similar or varied “mitigation” techniques. (See a very enlightening post by Onur Mutlu on TRR here: https://lnkd.in/gFZArTFJ ). Perhaps equal emphasis should be placed on significantly reducing or eliminating the underlying behavior as there is inventing the perfect band-aid!