RHEL 6 : kernel (RHSA-2019:1490)

high Nessus Plugin ID 125977

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Synopsis

The remote Red Hat host is missing one or more security updates for kernel.

Description

The remote Redhat Enterprise Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2019:1490 advisory.

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Security Fix(es):

* An integer overflow flaw was found in the way the Linux kernel's networking subsystem processed TCP Selective Acknowledgment (SACK) segments. While processing SACK segments, the Linux kernel's socket buffer (SKB) data structure becomes fragmented. Each fragment is about TCP maximum segment size (MSS) bytes. To efficiently process SACK blocks, the Linux kernel merges multiple fragmented SKBs into one, potentially overflowing the variable holding the number of segments. A remote attacker could use this flaw to crash the Linux kernel by sending a crafted sequence of SACK segments on a TCP connection with small value of TCP MSS, resulting in a denial of service (DoS). (CVE-2019-11477)

* kernel: Double free in lib/idr.c (CVE-2019-3896)

* Kernel: tcp: excessive resource consumption while processing SACK blocks allows remote denial of service (CVE-2019-11478)

* Kernel: tcp: excessive resource consumption for TCP connections with low MSS allows remote denial of service (CVE-2019-11479)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Bug Fix(es):

* MDS mitigations not enabled on Intel Skylake CPUs (BZ#1713025)

* [RHEL6] md_clear flag missing from /proc/cpuinfo (BZ#1713028)

* RHEL6 kernel does not disable SMT with mds=full,nosmt (BZ#1713043)

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the RHEL kernel package based on the guidance in RHSA-2019:1490.

Plugin Details

Severity: High

ID: 125977

File Name: redhat-RHSA-2019-1490.nasl

Version: 1.9

Type: local

Agent: unix

Family: Red Hat Local Security Checks

Published: 6/18/2019

Updated: 11/6/2024

Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.9

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 5.3

Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2019-3896

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

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

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:redhat:enterprise_linux:kernel, p-cpe:/a:redhat:enterprise_linux:kernel-headers, p-cpe:/a:redhat:enterprise_linux:kernel-firmware, p-cpe:/a:redhat:enterprise_linux:kernel-debug-devel, p-cpe:/a:redhat:enterprise_linux:python-perf, cpe:/o:redhat:rhel_aus:6.5, p-cpe:/a:redhat:enterprise_linux:kernel-devel, p-cpe:/a:redhat:enterprise_linux:kernel-debug, p-cpe:/a:redhat:enterprise_linux:perf

Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu

Exploit Ease: No known exploits are available

Patch Publication Date: 6/17/2019

Vulnerability Publication Date: 6/19/2019

Reference Information

CVE: CVE-2019-11477, CVE-2019-11478, CVE-2019-11479, CVE-2019-3896

CWE: 400, 416

RHSA: 2019:1490

Detections

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