CVE-2018-9056

Public on

Last Modified: UTC

Description

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).

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.

Additional information

  • Bugzilla 1561794: hw: cpu: speculative execution branch predictor side-channel attack
  • CWE-226: Sensitive Information in Resource Not Removed Before Reuse
  • FAQ: Frequently asked questions about CVE-2018-9056

Common Vulnerability Scoring System (CVSS) Score Details

Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).

The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 Score Breakdown
Red HatNVD

CVSS v3 Base Score

5.6

5.6

Attack Vector

Local

Local

Attack Complexity

High

High

Privileges Required

Low

Low

User Interaction

None

None

Scope

Changed

Changed

Confidentiality Impact

High

High

Integrity Impact

None

None

Availability Impact

None

None

CVSS v3 Vector

Red Hat: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

NVD: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

Frequently Asked Questions

Why is Red Hat's CVSS v3 score or Impact different from other vendors?

My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?

What can I do if my product is listed as "Will not fix"?

What can I do if my product is listed as "Fix deferred"?

What is a mitigation?

I have a Red Hat product but it is not in the above list, is it affected?

Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?

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