Linux distributions
TMA-ALMA9-3.3.1.20
Ensure net.ipv4.conf.default.route_localnet is configured
Description
The net.ipv4.conf.default.route_localnet flag sets, for newly added network interfaces, whether the system may use 127/8 for local routing purposes; when set to 0 the system continues to treat loopback addresses as martian source or destination while routing. 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
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 $f in configuration"; return 1;; esac; }; if chk net.ipv4.conf.default.route_localnet 0; then echo compliant; fi- Sortie attendue
compliant
Méthode de correction
Méthode de correction: Recommandation ou correctif d'infrastructure
Review all files being used by systemd sysctl and comment out or remove all net.ipv4.conf.default.route_localnet lines that are not net.ipv4.conf.default.route_localnet = 0. Example script #!/usr/bin/env bash { l_option="net.ipv4.conf.default.route_localnet" l_value="0" l_grep="${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 -- '…
Propriétés
- Systèmes d'exploitation
- almalinux-9
- Étiquettes
- cis-convertedkernellinuxsysctl
- Référence
- CIS AlmaLinux OS 9 Benchmark v3.0.0 - 3.3.1.20
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