Linux distributions
TMA-ROCKY9-3.3.1.1
Ensure net.ipv4.ip_forward is configured
Description
The net.ipv4.ip_forward flag tells the system whether it can forward IPv4 packets or not. 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. • If net.ipv4.conf.all.forwarding=0 and net.ipv4.conf.default.forwarding=0 are configured, this recommendation may be skipped.
Méthode de vérification
Méthode d'audit: Commande 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 $f in configuration"; return 1;; esac; }; if chk net.ipv4.ip_forward 0; then echo compliant; fi- Sortie attendue
compliant
Méthode de correction
Méthode de correction: Recommandation ou correctif d'infrastructure
1. Review all files being used by systemd-sysctl and comment out or remove all net.ipv4.ip_forward lines that are not net.ipv4.ip_forward=0. Example script: #!/usr/bin/env bash { l_option="net.ipv4.ip_forward" l_value="0" l_grep="${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*\/[^#\n\r\h]+\.conf\b') for l_file in "${…
Propriétés
- Systèmes d'exploitation
- rocky-9
- Étiquettes
- cis-convertedkernellinuxsysctl
- Référence
- CIS Rocky Linux 9 Benchmark v3.0.0 - 3.3.1.1
Vérifier cet hôte
Exécutez cette commande sur une machine que vous êtes autorisé à auditer. L'analyse est en lecture seule.
tmaegis scan --target linux