ALAS2-2019-1212


Amazon Linux 2 Security Advisory: ALAS2-2019-1212
Advisory Released Date: 2019-05-16
Advisory Updated Date: 2025-04-08
Severity: Important

Issue Overview:

Modern Intel microprocessors implement hardware-level micro-optimizations to improve the performance of writing data back to CPU caches. The write operation is split into STA (STore Address) and STD (STore Data) sub-operations. These sub-operations allow the processor to hand-off address generation logic into these sub-operations for optimized writes. Both of these sub-operations write to a shared distributed processor structure called the 'processor store buffer'. As a result, an unprivileged attacker could use this flaw to read private data resident within the CPU's processor store buffer. (CVE-2018-12126)

Microprocessors use a 'load port' subcomponent to perform load operations from memory or IO. During a load operation, the load port receives data from the memory or IO subsystem and then provides the data to the CPU registers and operations in the CPU's pipelines. Stale load operations results are stored in the 'load port' table until overwritten by newer operations. Certain load-port operations triggered by an attacker can be used to reveal data about previous stale requests leaking data back to the attacker via a timing side-channel. (CVE-2018-12127)

A flaw was found in the implementation of the "fill buffer", a mechanism used by modern CPUs when a cache-miss is made on L1 CPU cache. If an attacker can generate a load operation that would create a page fault, the execution will continue speculatively with incorrect data from the fill buffer while the data is fetched from higher level caches. This response time can be measured to infer data in the fill buffer. (CVE-2018-12130)

Uncacheable memory on some microprocessors utilizing speculative execution may allow an authenticated user to potentially enable information disclosure via a side channel with local access. (CVE-2019-11091)

A flaw was found in the Linux kernel's implementation of RDS over TCP. A system that has the rds_tcp kernel module loaded (either through autoload via local process running listen(), or manual loading) could possibly cause a use after free (UAF) in which an attacker who is able to manipulate socket state while a network namespace is being torn down. This can lead to possible memory corruption and privilege escalation. (CVE-2019-11815)


Affected Packages:

kernel


Note:

This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.


Issue Correction:
Run yum update kernel to update your system.

New Packages:
aarch64:
    kernel-4.14.114-105.126.amzn2.aarch64
    kernel-headers-4.14.114-105.126.amzn2.aarch64
    kernel-debuginfo-common-aarch64-4.14.114-105.126.amzn2.aarch64
    perf-4.14.114-105.126.amzn2.aarch64
    perf-debuginfo-4.14.114-105.126.amzn2.aarch64
    python-perf-4.14.114-105.126.amzn2.aarch64
    python-perf-debuginfo-4.14.114-105.126.amzn2.aarch64
    kernel-tools-4.14.114-105.126.amzn2.aarch64
    kernel-tools-devel-4.14.114-105.126.amzn2.aarch64
    kernel-tools-debuginfo-4.14.114-105.126.amzn2.aarch64
    kernel-devel-4.14.114-105.126.amzn2.aarch64
    kernel-debuginfo-4.14.114-105.126.amzn2.aarch64

i686:
    kernel-headers-4.14.114-105.126.amzn2.i686

src:
    kernel-4.14.114-105.126.amzn2.src

x86_64:
    kernel-4.14.114-105.126.amzn2.x86_64
    kernel-headers-4.14.114-105.126.amzn2.x86_64
    kernel-debuginfo-common-x86_64-4.14.114-105.126.amzn2.x86_64
    perf-4.14.114-105.126.amzn2.x86_64
    perf-debuginfo-4.14.114-105.126.amzn2.x86_64
    python-perf-4.14.114-105.126.amzn2.x86_64
    python-perf-debuginfo-4.14.114-105.126.amzn2.x86_64
    kernel-tools-4.14.114-105.126.amzn2.x86_64
    kernel-tools-devel-4.14.114-105.126.amzn2.x86_64
    kernel-tools-debuginfo-4.14.114-105.126.amzn2.x86_64
    kernel-devel-4.14.114-105.126.amzn2.x86_64
    kernel-debuginfo-4.14.114-105.126.amzn2.x86_64

Changelog:

2025-04-08: CVE-2019-11091 was added to this advisory.

2025-04-08: CVE-2018-12130 was added to this advisory.

2025-04-08: CVE-2018-12127 was added to this advisory.

2025-04-08: CVE-2018-12126 was added to this advisory.