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TMA-ROCKY9-3.3.1.4

Ensure net.ipv4.conf.all.send_redirects is configured

MoyenneNiveau 1Automatiséelinux

Description

ICMP Redirects are used to send routing information to other hosts. As a host itself does not act as a router (in a host only configuration), there is no need to send redirects. net.ipv4.conf.all.send_redirects controls sending 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. 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.all.send_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.send_redirects lines that are not net.ipv4.conf.all.send_redirects=0. Example script: #!/usr/bin/env bash { l_option="net.ipv4.conf.all.send_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*#\h*\/…

Propriétés

Systèmes d'exploitation
rocky-9
Étiquettes
cis-convertedkernellinuxsysctl
Référence
CIS Rocky Linux 9 Benchmark v3.0.0 - 3.3.1.4

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