Hardware Security

Which is a countermeasure against DRAM Rowhammer?

  1. AHalving DRAM capacity
  2. BRefreshing rows adjacent to frequently activated rows early (such as TRR), or increasing the refresh rate
  3. CStopping the CPU clock
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Answer: B. Refreshing rows adjacent to frequently activated rows early (such as TRR), or increasing the refresh rate

Rowhammer is the phenomenon in which activating a row many times in a short period causes electrical interference that drains charge from cells in neighboring rows, flipping bits. It could let unprivileged programs alter other processes' or kernel data. Countermeasures combine mechanisms that additionally refresh neighbors of heavily activated rows, higher refresh rates and ECC to detect and correct flips.

  • A. Reducing capacity is not a countermeasure.
  • B. Correct. Cells are rewritten before their charge leaks away.
  • C. Stopping the clock halts operation.
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More Hardware Security questions

  1. Which correctly pairs why cold boot attacks work with a typical countermeasure?
  2. Which describes secure boot?
  3. What is the most suitable thing placed inside the chip as the root of trust for secure boot?
  4. What is the advantage of using public-key cryptography to verify software signatures in secure boot?
  5. In devices with secure boot, why is an anti-rollback mechanism needed?