QID 353138

Date Published: 2022-02-01

QID 353138: Amazon Linux Security Advisory for kernel : ALAS2KERNEL-5.4-2022-013

A logic bug flaw was found in the linux kernel's implementation of ssbd.
A bug in the logic handling allows an attacker with a local account to disable ssbd protection during a context switch when additional speculative execution mitigations are in place.
This issue was introduced when the per task/process conditional stipb switching was added on top of the existing ssbd switching.
The highest threat from this vulnerability is to confidentiality. (
( CVE-2020-10766) a flaw was found in the linux kernel's implementation of the enhanced ibpb (indirect branch prediction barrier).
The ibpb mitigation will be disabled when stibp is not available or when the enhanced indirect branch restricted speculation (ibrs) is available.
This flaw allows a local attacker to perform a spectre v2 style attack when this configuration is active.
( CVE-2020-10767) a flaw was found in the prctl() function, where it can be used to enable indirect branch speculation after it has been disabled.
This call incorrectly reports it as being 'force disabled' when it is not and opens the system to spectre v2 attacks.
( CVE-2020-10768) an issue was discovered in the linux kernel through 5.6.11.
Btree_gc_coalesce in drivers/md/bcache/btree.c has a deadlock if a coalescing operation fails. (
( CVE-2020-12771)

Note: The preceding description block is extracted directly from the security advisory. Using automation, we have attempted to clean and format it as much as possible without introducing additional issues.

Successful exploitation of this vulnerability could lead to a securitybreach or could affect integrity, availability, and confidentiality.

CVSS V3 rated as Medium - 5.5 severity.

CVSS V2 rated as Low - 2.1 severity.

Solution

Please refer to Amazon advisory: ALAS2KERNEL-5.4-2022-013 for affected packages and patching details, or update with your package manager.

Vendor References

ALAS2KERNEL-5.4-2022-013 - alas.aws.amazon.com/AL2/ALASKERNEL-5.4-2022-013.html

CVEs related to QID 353138

CVE-2020-10767 | CVE-2020-10768 | CVE-2020-10766 | CVE-2020-12771 |

Software Advisories

Advisory ID	Software	Component	Link
ALAS2KERNEL-5.4-2022-013	Amazon Linux 2		alas.aws.amazon.com/AL2/ALASKERNEL-5.4-2022-013.html

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