Spectre rises from the dead to bite Intel in the return stack buffer

Spectre, a class of vulnerabilities in the speculative execution mechanism employed in modern processor chips, is living up to its name by proving to be unkillable.

Amid a series of mitigations proposed by Intel, Google and others, recent claims by Dartmouth computer scientists to have solved Spectre variant 1, and a proposed chip design fix called SafeSpec, new variants and sub-variants keep appearing.

The findings also revive doubts about whether current and past chip designs can ever be truly fixed.