Arch Linux Security Advisory ASA-201808-7 ========================================= Severity: High Date : 2018-08-08 CVE-ID : CVE-2018-5390 Package : linux-hardened Type : denial of service Remote : Yes Link : https://security.archlinux.org/AVG-750 Summary ======= The package linux-hardened before version 4.17.11.a-1 is vulnerable to denial of service. 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. Workaround ========== None. Description =========== 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. Impact ====== A remote attacker is able to saturate the CPU and hence cause a denial of service on the host system by sending specially modified packets within ongoing TCP sessions. References ========== https://www.kb.cert.org/vuls/id/962459 https://www.spinics.net/lists/netdev/msg514742.html https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=7... https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=f... https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=3... https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=8... https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=5... https://security.archlinux.org/CVE-2018-5390