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).
Find out more about CVE-2018-9056 from the MITRE CVE dictionary dictionary and NIST NVD.
NOTE: The following CVSS v3 metrics and score provided are preliminary and subject to review.
CVSS3 Base Score | 5.6 |
---|---|
CVSS3 Base Metrics | CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N |
Attack Vector | Local |
Attack Complexity | High |
Privileges Required | Low |
User Interaction | None |
Scope | Changed |
Confidentiality | High |
Integrity Impact | None |
Availability Impact | None |
Platform | Package | State |
---|---|---|
Red Hat Enterprise MRG 2 | realtime-kernel | Not affected |
Red Hat Enterprise Linux 7 | kernel-alt | Not affected |
Red Hat Enterprise Linux 7 | kernel | Not affected |
Red Hat Enterprise Linux 7 | kernel-rt | Not affected |
Red Hat Enterprise Linux 6 | kernel | Not affected |
Red Hat Enterprise Linux 5 | kernel | Not affected |
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.