News Rowhammer Attacks Pushed Through Despite Security Mitigations

[Admin]

Researchers found ways to conduct Rowhammer attacks on DDR4 RAM despite the industry's mitigations.

Rowhammer Attacks Pushed Through Despite Security Mitigations : Read more

 

[digitalgriffin]

Fascinating.

Memory needs to be constantly refreshed to keep it's contents. That's why you lose contents when powers off. However writing new values causes a temporary surge in power to change the bits. This leads to a small EMF (Magnetic field) surge as well. When you hit the same row line over and over again this causes the field to build, till the magnetic field spills over in the adjacent row. This causes the bits to flip. That's how row hammer works. It affected DDR3.

That said, it WAS to be mitigated by restricting how fast the same row could be written too. If they found they could still flip bits, I would be betting it would be on faster memory that runs on a higher voltages. (1.35V)

 

[Rob1C]

There's some more information here: https://nvd.nist.gov/vuln/detail/CVE-2020-10255 and AMD has commented on some mitigations for this newest RowHammer https://www.amd.com/en/corporate/product-security - on Epyc (with memory encryption) a DOS is likely the worst that can happen.