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CVE-2021-35477

Опубликовано: 01 авг. 2021
Источник: redhat
CVSS3: 4.4
EPSS Низкий

Описание

In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because a certain preempting store operation does not necessarily occur before a store operation that has an attacker-controlled value.

A flaw in the Linux kernel allows a privileged BPF program to obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel in the eBPF subsystem

Меры по смягчению последствий

The default Red Hat Enterprise Linux kernel setting prevents unprivileged users from being able to use eBPF via the kernel.unprivileged_bpf_disabled sysctl. As such, exploiting this issue would require a privileged user with CAP_SYS_ADMIN or root. 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 (default) would mean that unprivileged users cannot use eBPF. Otherwise, to disable eBPF for unprivileged users, add: kernel.unprivileged_bpf_disabled = 1 To the file "/etc/sysctl.d/disable-ebpf.conf" Then running the following command as root:

sudo sysctl --system

Затронутые пакеты

ПлатформаПакетСостояниеРекомендацияРелиз
Red Hat Enterprise Linux 6kernelOut of support scope
Red Hat Enterprise Linux 7kernelOut of support scope
Red Hat Enterprise Linux 7kernel-altOut of support scope
Red Hat Enterprise Linux 7kernel-rtOut of support scope
Red Hat Enterprise Linux 8kernelAffected
Red Hat Enterprise Linux 8kernel-rtAffected
Red Hat Enterprise Linux 9kernelNot affected

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Дополнительная информация

Статус:

Moderate
Дефект:
CWE-200
https://bugzilla.redhat.com/show_bug.cgi?id=1989216kernel: BPF program can obtain sensitive information from kernel memory via a speculative store bypass side-channel attack because the technique used by the BPF verifier to manage speculation is unreliable

EPSS

Процентиль: 13%
0.00043
Низкий

4.4 Medium

CVSS3

Связанные уязвимости

CVSS3: 5.5
ubuntu
больше 4 лет назад

In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because a certain preempting store operation does not necessarily occur before a store operation that has an attacker-controlled value.

CVSS3: 5.5
nvd
больше 4 лет назад

In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because a certain preempting store operation does not necessarily occur before a store operation that has an attacker-controlled value.

CVSS3: 5.5
msrc
больше 4 лет назад

In the Linux kernel through 5.13.7 an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because a certain preempting store operation does not necessarily occur before a store operation that has an attacker-controlled value.

CVSS3: 5.5
debian
больше 4 лет назад

In the Linux kernel through 5.13.7, an unprivileged BPF program can ob ...

github
больше 3 лет назад

In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because a certain preempting store operation does not necessarily occur before a store operation that has an attacker-controlled value.

EPSS

Процентиль: 13%
0.00043
Низкий

4.4 Medium

CVSS3