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TMA-ROCKY8-3.3.1.13

Ensure net.ipv4.conf.default.rp_filter is configured

OrtaDüzey 1Otomatiklinux

Açıklama

net.ipv4.conf.default.rp_filter controls reverse path filtering for IPv4 traffic on newly added network interfaces. Reverse path filtering is a security mechanism in Linux that helps prevent IP spoofing and other network attacks. When enabled, it checks if the source IP address of an incoming packet is reachable through the same network interface it was received on. If the packet's source address is not reachable through the interface it arrived on, the packet is dropped. Note: If this system is a router, and uses asymmetrical routing, this recommendation is not applicable.

Nasıl denetlenir

Denetim yöntemi: Kabuk komutu

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.rp_filter 1; then echo compliant; fi
Beklenen çıktı
compliant

Nasıl düzeltilir

Düzeltme yöntemi: Kılavuz veya altyapı yaması

1. Review all files being used by systemd sysctl and comment out or remove all net.ipv4.conf.default.rp_filter lines that are not net.ipv4.conf.default.rp_filter=1. Example script: #!/usr/bin/env bash { l_option="net.ipv4.conf.default.rp_filter" l_value="1" l_grep="${l_option//./(\\.|\\/)}" a_files=() l_systemdsysctl="$(readlink -e /lib/systemd/systemd-sysctl \ || readlink -e /usr/lib/systemd/systemd-sysctl)" l_ufw_file="$([ -f /etc/default/ufw ] && \ awk -F= '/^\s*IPT_SYSCTL=/ {print $2}' /etc/default/ufw)" [ -f "$(readlink -e "$l_ufw_file")" ] && \ a_files+=("$l_ufw_file"); a_files+=("/etc/sysctl.conf") while IFS= read -r l_fname; do l_file="$(readlink -e "${l_fname//# /}")" [ -n "$l_file"…

Özellikler

İşletim sistemleri
rocky-8
Etiketler
cis-convertedkernellinuxsysctl
Referans
CIS Rocky Linux 8 Benchmark v3.0.0 - 3.3.1.13

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shell
tmaegis scan --target linux