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New Rowhammer Technique

published on 2021-11-19 14:31:14 UTC by Bruce Schneier
Content:

Rowhammer is an attack technique involving accessing — that’s “hammering” — rows of bits in memory, millions of times per second, with the intent of causing bits in neighboring rows to flip. This is a side-channel attack, and the result can be all sorts of mayhem.

Well, there is a new enhancement:

All previous Rowhammer attacks have hammered rows with uniform patterns, such as single-sided, double-sided, or n-sided. In all three cases, these “aggressor” rows — meaning those that cause bitflips in nearby “victim” rows — are accessed the same number of times.

Research published on Monday presented a new Rowhammer technique. It uses non-uniform patterns that access two or more aggressor rows with different frequencies. The result: all 40 of the randomly selected DIMMs in a test pool experienced bitflips, up from 13 out of 42 chips tested in previous work from the same researchers.

[…]

The non-uniform patterns work against Target Row Refresh. Abbreviated as TRR, the mitigation works differently from vendor to vendor but generally tracks the number of times a row is accessed and recharges neighboring victim rows when there are signs of abuse. The neutering of this defense puts further pressure on chipmakers to mitigate a class of attacks that many people thought more recent types of memory chips were resistant to.

Article: New Rowhammer Technique - published almost 3 years ago.

https://www.schneier.com/blog/archives/2021/11/new-rowhammer-technique.html   
Published: 2021 11 19 14:31:14
Received: 2021 11 19 15:05:37
Feed: Schneier on Security
Source: Schneier on Security
Category: Cyber Security
Topic: Cyber Security
Views: 2

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