Blessed SMoTherSpectre, Who Listened to the Branch

Patron of branch prediction, processors that guess, and secrets that leak through timing.

Life

On 6 March 2019 a group of researchers from EPFL and IBM presented SMoTherSpectre, a variant of the speculative-execution vulnerabilities. By pushing the processor to predict an indirect branch toward a chosen code fragment, and carefully measuring how long it took to run, bits of another program's confidential data could be inferred, exploiting the contention between execution units.

Prayer

O Blessed SMoTherSpectre, who listens for secrets in the rhythm of branches, keep our processors from guessing what they shouldn't. Amen.

How to celebrate

Celebrated by applying the Spectre mitigations, hardening the boundaries between programs, and measuring twice before trusting timing.

Guess the branch, and you eavesdrop on the thought.