Ensure secure ICMP redirects are not accepted

MoyenneNiveau 1Automatiséelinux

Description

Secure ICMP redirects are the same as ICMP redirects, except they come from gateways listed on the default gateway list. It is assumed that these gateways are known to your system, and that they are likely to be secure.

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.secure_redirects 0 && chk net.ipv4.conf.default.secure_redirects 0; then echo compliant; fi

Sortie attendue: compliant

Méthode de correction

Méthode de correction: Recommandation ou correctif d'infrastructure

Set the following parameters in /etc/sysctl.conf or a /etc/sysctl.d/* file: net.ipv4.conf.all.secure_redirects = 0 net.ipv4.conf.default.secure_redirects = 0 Run the following commands to set the active kernel parameters: # sysctl -w net.ipv4.conf.all.secure_redirects=0 # sysctl -w net.ipv4.conf.default.secure_redirects=0 # sysctl -w net.ipv4.route.flush=1

Propriétés

Systèmes d'exploitation: alinux-2
Étiquettes: cis-convertedkernellinuxsysctl
Référence: CIS Aliyun Linux 2 Benchmark v1.0.0 ARCHIVE - 3.2.3

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