Since 2018, an almost endless series of attacks broadly known as Spectre has kept Intel and AMD scrambling to develop defenses that mitigate vulnerabilities that allow malware to pluck passwords and other sensitive information directly out of silicon. Now, researchers say they’ve devised a new attack that breaks most—if not all—of those on-chip defenses.
Spectre got its name for its abuse of speculative execution, a feature in virtually all modern CPUs that predicts future instructions they might receive and then follows a path they’re likely to follow. By using code that forces a CPU to execute instructions along the wrong path, Spectre can extract confidential data that would have been accessed had the CPU continued down that wrong path. These exploits are known as transient executions.
“Dangerous implications”
Since Spectre was first described in 2018, new variants have surfaced almost every month. In many cases, the new variants have required chipmakers to develop new or augmented defenses to mitigate the attacks.