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TMA-ALMA9-3.3.2.3

Ensure net.ipv6.conf.all.accept_redirects is configured

MittelStufe 1Automatisiertlinux

Beschreibung

ICMP redirect messages are packets that convey routing information and tell your host (acting as a router) to send packets via an alternate path. It is a way of allowing an outside routing device to update your system routing tables. net.ipv6.conf.all.accept_redirects controls accepting of all IPv6 ICMP redirected packets on all interfaces. More information about the kernel parameter configuration files, their location, and load preference is available in the "Configure Network Kernel Parameters" section overview. Note: If IPv6 has been disabled, or this system is a router, this recommendation

So wird geprüft

Prüfmethode: Shell-Befehl

shell
chk() { p=$1; allowed=" $2 "; case $p in net.ipv6.*) [ -d /proc/sys/net/ipv6 ] || return 0;; esac; v=$(sysctl -n "$p" 2>/dev/null) || { echo "$p: not available"; return 1; }; case "$allowed" in *" $v "*) ;; *) echo "$p is $v (running)"; return 1;; esac; sd=$(readlink -e /lib/systemd/systemd-sysctl || readlink -e /usr/lib/systemd/systemd-sysctl); f=$("$sd" --cat-config 2>/dev/null | grep -Po "^\h*${p//./\.}\h*=\h*\K\H+" | tail -n1); [ -n "$f" ] || { echo "$p is not set in any sysctl configuration file"; return 1; }; case "$allowed" in *" $f "*) ;; *) echo "$p is $f in configuration"; return 1;; esac; }; if chk net.ipv6.conf.all.accept_redirects 0; then echo compliant; fi
Erwartete Ausgabe
compliant

So wird behoben

Behebungsmethode: Anleitung oder Infrastruktur-Patch

1. Review all files being used by systemd sysctl and comment out or remove all net.ipv6.conf.all.accept_redirects lines that are not net.ipv6.conf.all.accept_redirects=0. Example script: #!/usr/bin/env bash { l_option="net.ipv6.conf.all.accept_redirects" l_value="0" l_grep="${l_option//./(\\.|\\/)}" a_files=() l_systemdsysctl="$(readlink -e /lib/systemd/systemd-sysctl \ || readlink -e /usr/lib/systemd/systemd-sysctl)" a_files+=("/etc/sysctl.conf") while IFS= read -r l_fname; do l_file="$(readlink -e "${l_fname//# /}")" [ -n "$l_file" ] && ! grep -Psiq -- '(^|\h+)'"$l_file"'\b' \ <<< "${a_files[*]}" && a_files+=("$l_file") done < <("$l_systemdsysctl" --cat-config | tac | \ grep -Psio -- '^\h*…

Eigenschaften

Betriebssysteme
almalinux-9
Tags
cis-convertedkernellinuxsysctl
Referenz
CIS AlmaLinux OS 9 Benchmark v3.0.0 - 3.3.2.3

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