Linux distributions
TMA-ALMA9-3.3.2.3
Ensure net.ipv6.conf.all.accept_redirects is configured
Descrição
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
Como é verificado
Método de auditoria: Comando 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 $f in configuration"; return 1;; esac; }; if chk net.ipv6.conf.all.accept_redirects 0; then echo compliant; fi- Saída esperada
compliant
Como é corrigido
Método de correção: Orientação ou patch de infraestrutura
1. Review all files being used by systemd sysctl and comment out or remove all net.ipv6.conf.all.accept_redirects lines that are not net.ipv6.conf.all.accept_redirects=0. Example script: #!/usr/bin/env bash { l_option="net.ipv6.conf.all.accept_redirects" l_value="0" l_grep="${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*…
Propriedades
- Sistemas operacionais
- almalinux-9
- Tags
- cis-convertedkernellinuxsysctl
- Referência
- CIS AlmaLinux OS 9 Benchmark v3.0.0 - 3.3.2.3
Verificar este host
Execute isto em uma máquina que você tenha permissão para auditar. A varredura é somente leitura.
tmaegis scan --target linux