ArchLinux: 201808-7: linux-hardened: denial of service
Summary
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.
Resolution
Upgrade to 4.17.11.a-1.
# pacman -Syu "linux-hardened>=4.17.11.a-1"
The problem has been fixed upstream in version 4.17.11.a.
References
https://www.kb.cert.org/vuls/id/962459 https://www.spinics.net/lists/netdev/msg514742.html https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ https://security.archlinux.org/CVE-2018-5390
![Dist Arch](/images/distros/dist-arch.png)
Workaround
None.