Linux distributions
TMA-ALMA9-3.3.2.3
Ensure net.ipv6.conf.all.accept_redirects is configured
Descripción
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.ipv6.conf.all.accept_redirects controls accepting of all IPv6 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 IPv6 has been disabled, or this system is a router, this recommendation
Cómo se verifica
Método de auditoría: Comando de 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 $f in configuration"; return 1;; esac; }; if chk net.ipv6.conf.all.accept_redirects 0; then echo compliant; fi- Salida esperada
compliant
Cómo se corrige
Método de corrección: Guía o parche de infraestructura
1. Review all files being used by systemd sysctl and comment out or remove all net.ipv6.conf.all.accept_redirects lines that are not net.ipv6.conf.all.accept_redirects=0. Example script: #!/usr/bin/env bash { l_option="net.ipv6.conf.all.accept_redirects" l_value="0" l_grep="${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*…
Propiedades
- Sistemas operativos
- almalinux-9
- Etiquetas
- cis-convertedkernellinuxsysctl
- Referencia
- CIS AlmaLinux OS 9 Benchmark v3.0.0 - 3.3.2.3
Verificar este host
Ejecute esto en un equipo que tenga permiso para auditar. El escaneo es de solo lectura.
tmaegis scan --target linux