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TMA-ROCKY9-3.3.1.8

Ensure net.ipv4.conf.all.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.all.accept_redirects controls accepting of all IPv4 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.

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.all.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.all.accept_redirects lines that are not net.ipv4.conf.all.accept_redirects=0. Example script: #!/usr/bin/env bash { l_option="net.ipv4.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*…

Propriétés

Systèmes d'exploitation
rocky-9
Étiquettes
cis-convertedkernellinuxsysctl
Référence
CIS Rocky Linux 9 Benchmark v3.0.0 - 3.3.1.8

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