CVE-2018-5390 "SegmentSmack" - remote denial of service attack

This document (7023243) is provided subject to the disclaimer at the end of this document.


SUSE Linux Enterprise Server 15


"SegmentSmack" CVE-2018-5390 remote denial of service attack

Security researchers from FICORA have identified a remote denial of
service attack against the Linux kernel caused by inefficient
implementation of TCP segment reassembly, named "SegmentSmack".

A remote attacker could consume a lot of CPU resources in the kernel
networking stack with just a low bandwidth or single host attack by
using lots of small TCP segments packets. Usually large botnets are
needed for similar effect.

The rate needed for this denial of service attack to be effective is
several magnitudes lower than the usual packet processing capability of
the machine, as the attack exploits worst case behaviour of existing

This attack affects Linux Kernels 4.9 and later, so it affects only
SUSE Linux Enterprise 15.


Fixes for these issues are provided as maintenance updates supplied by SUSE.
First kernel version  containing the fix is 4.12.14-25.6.1.
CVE-2018-5390 is mentioned in the package changelog.


Additional Information


For "SegmentSmack" there is no workaround is known at this time, only
applying the patch will help.

See also:


This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.

  • Document ID:7023243
  • Creation Date: 03-Aug-2018
  • Modified Date:03-Mar-2020
    • SUSE Linux Enterprise Server

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