Which processor vulnerability allows attackers to exploit speculative execution to read restricted data across security boundaries?

Which processor vulnerability allows attackers to exploit speculative execution to read restricted data across security boundaries?

• A. Meltdown Vulnerability
• B. Rowhammer
• C. Side-channel Attack
• D. Spectre Vulnerability

Answer: (D)

Speculative execution can speed up a CPU by guessing the next steps and executing them ahead of time. If the guessed path touches data it shouldn’t access, the processor might still perform those reads and leave behind microarchitectural traces, such as cached data patterns. An attacker can exploit this by triggering mispredicted branches so that the processor speculatively reads sensitive information from across security boundaries, then observes the resulting side effects (often through timing or cache behavior) to reconstruct the secret. This cross-boundary data leakage via speculative execution is what the Spectre vulnerability is all about.

Speculative execution can speed up a CPU by guessing the next steps and executing them ahead of time. If the guessed path touches data it shouldn’t access, the processor might still perform those reads and leave behind microarchitectural traces, such as cached data patterns. An attacker can exploit this by triggering mispredicted branches so that the processor speculatively reads sensitive information from across security boundaries, then observes the resulting side effects (often through timing or cache behavior) to reconstruct the secret. This cross-boundary data leakage via speculative execution is what the Spectre vulnerability is all about.