RHEL 6 : MRG (RHSA-2018:2789)

High Nessus Plugin ID 117816


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


An update for kernel-rt is now available for Red Hat Enterprise MRG 2.

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-rt packages provide the Real Time Linux Kernel, which
enables fine-tuning for systems with extremely high determinism

Security Fix(es) :

* A flaw named SegmentSmack was found in the way the Linux kernel
handled specially crafted TCP packets. A remote attacker could use
this flaw to trigger time and calculation expensive calls to
tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() functions by
sending specially modified packets within ongoing TCP sessions which
could lead to a CPU saturation and hence a denial of service on the
system. Maintaining the denial of service condition requires
continuous two-way TCP sessions to a reachable open port, thus the
attacks cannot be performed using spoofed IP addresses.

Red Hat would like to thank Juha-Matti Tilli (Aalto University -
Department of Communications and Networking and Nokia Bell Labs) for
reporting this issue.

Bug Fix(es) :

* The kernel-rt packages have been upgraded to the 3.10.0-693.39.1
source tree, which provides a number of bug fixes over the previous
version. (BZ# 1616431)

* Previously, preemption was enabled too early after a context switch.
If a task was migrated to another CPU after a context switch, a
mismatch between CPU and runqueue during load balancing sometimes
occurred. Consequently, a runnable task on an idle CPU failed to run,
and the operating system became unresponsive. This update disables
preemption in the schedule_tail() function. As a result, CPU migration
during post-schedule processing no longer occurs, which prevents the
above mismatch. The operating system no longer hangs due to this bug.


Update the affected packages.

See Also



Plugin Details

Severity: High

ID: 117816

File Name: redhat-RHSA-2018-2789.nasl

Version: 1.3

Type: local

Agent: unix

Published: 2018/09/28

Modified: 2018/11/10

Dependencies: 12634

Risk Information

Risk Factor: High

CVSS v2.0

Base Score: 7.8

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

CVSS v3.0

Base Score: 7.5

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

Vulnerability Information

CPE: p-cpe:/a:redhat:enterprise_linux:kernel-rt, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-debuginfo, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-devel, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debuginfo, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debuginfo-common-x86_64, p-cpe:/a:redhat:enterprise_linux:kernel-rt-devel, p-cpe:/a:redhat:enterprise_linux:kernel-rt-doc, p-cpe:/a:redhat:enterprise_linux:kernel-rt-firmware, p-cpe:/a:redhat:enterprise_linux:kernel-rt-trace, p-cpe:/a:redhat:enterprise_linux:kernel-rt-trace-debuginfo, p-cpe:/a:redhat:enterprise_linux:kernel-rt-trace-devel, p-cpe:/a:redhat:enterprise_linux:kernel-rt-vanilla, p-cpe:/a:redhat:enterprise_linux:kernel-rt-vanilla-debuginfo, p-cpe:/a:redhat:enterprise_linux:kernel-rt-vanilla-devel, cpe:/o:redhat:enterprise_linux:6

Patch Publication Date: 2018/09/25

Reference Information

CVE: CVE-2018-5390

RHSA: 2018:2789