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MEDIUM

hw: cpu: arm64: Spectre-BHB

Published Mar 12, 2022

Description

Certain Arm Cortex and Neoverse processors through 2022-03-08 do not properly restrict cache speculation, aka Spectre-BHB. An attacker can leverage the shared branch history in the Branch History Buffer (BHB) to influence mispredicted branches. Then, cache allocation can allow the attacker to obtain sensitive information.

Affected products

Remediation

Red Hat statement

The current known mechanisms to exploit this issue rely on unprivileged eBPF functionality. Unprivileged eBPF is disabled by default on Red Hat Enterprise Linux.

Red Hat mitigation

Disabling unprivileged eBPF effectively mitigates the known attack vectors for exploiting intra-mode branch injections attacks. The default Red Hat Enterprise Linux kernel prevents unprivileged users from being able to use eBPF by the kernel.unprivileged_bpf_disabled sysctl. For the Red Hat Enterprise Linux 7, the eBPF for unprivileged users is always disabled. For the Red Hat Enterprise Linux 8 to confirm the current state, inspect the sysctl with the command: # cat /proc/sys/kernel/unprivileged_bpf_disabled The setting of 1 would mean that unprivileged users can not use eBPF, mitigating the flaw.

Metrics

Weaknesses (0)

No CWE recorded.

References (10)

Change history (0)

No recorded changes yet.

Sources
CVE.org / MITRE
Status PUBLISHED
Assigner mitre
Published Mar 12, 2022
Updated Aug 3, 2024
Reserved Jan 26, 2022
NVD
Status Modified
Modified Jun 17, 2026
Red Hat
Severity Moderate
Public date Mar 8, 2022