CVE-2018-9056

BranchScope is a new class of attack which leverages functioning of the Branch Prediction Unit (BPU) of a processor to infer/leak sensitive process information, which is involved in the branch decision making (if (x) { x ^ y; } else {x & y;}). In this, BranchScope side-channel could help to infer ‘x’, by observing prediction patterns of the Branch Prediction Unit (BPU).

Mitigation

This is a hardware processor issue, not a Linux kernel flaw. The flaw specifically targets software which uses sensitive information in branching expressions. A software mitigation could be for the target software to avoid the use of sensitive data bits in (if…else) branching decisions or to avoid (if…else) branching altogether.