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TMA-ROCKY8-3.3.1.9

Ensure net.ipv4.conf.default.accept_redirects is configured

MoyenneNiveau 1Automatiséelinux

Description

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.ipv4.conf.default.accept_redirects controls accepting of all IPv4 ICMP redirected packets on a newly added network interface. Note: If this system is a router this recommendation is not applicable.

Méthode de vérification

Méthode d'audit: Commande shell

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.ipv4.conf.default.accept_redirects 0; then echo compliant; fi
Sortie attendue
compliant

Méthode de correction

Méthode de correction: Recommandation ou correctif d'infrastructure

1. Review all files being used by systemd sysctl and comment out or remove all net.ipv4.conf.default.accept_redirects lines that are not net.ipv4.conf.default.accept_redirects=0. Example script: #!/usr/bin/env bash { l_option="net.ipv4.conf.default.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)" l_ufw_file="$([ -f /etc/default/ufw ] && \ awk -F= '/^\s*IPT_SYSCTL=/ {print $2}' /etc/default/ufw)" [ -f "$(readlink -e "$l_ufw_file")" ] && \ a_files+=("$l_ufw_file"); a_files+=("/etc/sysctl.conf") while IFS= read -r l_fname; do l_file="$(readlink -e "${l_fname//#…

Propriétés

Systèmes d'exploitation
rocky-8
Étiquettes
cis-convertedkernellinuxsysctl
Référence
CIS Rocky Linux 8 Benchmark v3.0.0 - 3.3.1.9

Vérifier cet hôte

Exécutez cette commande sur une machine que vous êtes autorisé à auditer. L'analyse est en lecture seule.

shell
tmaegis scan --target linux