Protect yourself against future threats.
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AUSCERT External Security Bulletin Redistribution
ESB-2018.2342
linux security update
15 August 2018
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AusCERT Security Bulletin Summary
---------------------------------
Product: linux
Publisher: Debian
Operating System: Debian GNU/Linux 9
Linux variants
Impact/Access: Denial of Service -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2018-5391
Original Bulletin:
http://www.debian.org/security/2018/dsa-4272
Comment: This advisory references vulnerabilities in the Linux kernel that
also affect distributions other than Debian. It is recommended that
administrators running Linux check for an updated version of the
kernel for their system.
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Debian Security Advisory DSA-4272-1 security@debian.org
https://www.debian.org/security/ Salvatore Bonaccorso
August 14, 2018 https://www.debian.org/security/faq
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Package : linux
CVE ID : CVE-2018-5391
CVE-2018-5391 (FragmentSmack)
Juha-Matti Tilli discovered a flaw in the way the Linux kernel
handled reassembly of fragmented IPv4 and IPv6 packets. A remote
attacker can take advantage of this flaw to trigger time and
calculation expensive fragment reassembly algorithms by sending
specially crafted packets, leading to remote denial of service.
This is mitigated by reducing the default limits on memory usage
for incomplete fragmented packets. The same mitigation can be
achieved without the need to reboot, by setting the sysctls:
net.ipv4.ipfrag_high_thresh = 262144
net.ipv6.ip6frag_high_thresh = 262144
net.ipv4.ipfrag_low_thresh = 196608
net.ipv6.ip6frag_low_thresh = 196608
The default values may still be increased by local configuration
if necessary.
For the stable distribution (stretch), this problem has been fixed in
version 4.9.110-3+deb9u2.
We recommend that you upgrade your linux packages.
For the detailed security status of linux please refer to its security
tracker page at:
https://security-tracker.debian.org/tracker/linux
Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://www.debian.org/security/
Mailing list: debian-security-announce@lists.debian.org
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