What is "speculative store bypass" and how does it relate to security vulnerabilities like Spectre variant 4?
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Incorrect.
The correct answer is A) It is a CPU optimization where loads may speculatively execute before an earlier store to a potentially overlapping address completes, assuming no dependency; if wrong, this speculation can leak data via side channels, as exploited in Spectre variant 4
Correct Answer
It is a CPU optimization where loads may speculatively execute before an earlier store to a potentially overlapping address completes, assuming no dependency; if wrong, this speculation can leak data via side channels, as exploited in Spectre variant 4
CPUs may speculatively reorder loads ahead of stores to improve performance, betting that addresses don't overlap; Spectre v4 exploits cases where this speculation is incorrect, allowing an attacker to observe microarchitectural side effects of speculatively loaded (stale or future) values.