CentOS 6 : kernel (CESA-2019:1488) (SACK Panic) (SACK Slowness)

high Nessus Plugin ID 126007

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Synopsis

The remote CentOS host is missing one or more security updates.

Description

An update for kernel is now available for Red Hat Enterprise Linux 6.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

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#1710081)

* RHEL6 kernel does not disable SMT with mds=full,nosmt (BZ#1710121)

* [RHEL6] md_clear flag missing from /proc/cpuinfo (BZ#1710517)

Solution

Update the affected kernel packages.

Plugin Details

Severity: High

ID: 126007

File Name: centos_RHSA-2019-1488.nasl

Version: 1.7

Type: local

Agent: unix

Family: CentOS Local Security Checks

Published: 6/19/2019

Updated: 12/5/2022

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

Risk Information

VPR

Risk Factor: Medium

Score: 5.9

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:centos:centos:kernel-headers, cpe:/o:centos:centos:6, p-cpe:/a:centos:centos:kernel-debug, p-cpe:/a:centos:centos:kernel-abi-whitelists, p-cpe:/a:centos:centos:kernel-firmware, p-cpe:/a:centos:centos:perf, p-cpe:/a:centos:centos:python-perf, p-cpe:/a:centos:centos:kernel, p-cpe:/a:centos:centos:kernel-doc, p-cpe:/a:centos:centos:kernel-debug-devel, p-cpe:/a:centos:centos:kernel-devel

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

Exploit Ease: No known exploits are available

Patch Publication Date: 6/18/2019

Vulnerability Publication Date: 6/19/2019

Reference Information

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

RHSA: 2019:1488

Detections

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