Linux distributions
TMA-ROCKY9-3.3.1.13
Ensure net.ipv4.conf.default.rp_filter is configured
Beschreibung
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. More information about the kernel parameter configuration files, their location, and load preference is available in the "C
So wird geprüft
Prüfmethode: Shell-Befehl
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 $f in configuration"; return 1;; esac; }; if chk net.ipv4.conf.default.rp_filter 1; then echo compliant; fi- Erwartete Ausgabe
compliant
So wird behoben
Behebungsmethode: Anleitung oder Infrastruktur-Patch
1. Review all files being used by systemd sysctl and comment out or remove all net.ipv4.conf.default.rp_filter lines that are not net.ipv4.conf.default.rp_filter=1. Example script: #!/usr/bin/env bash { l_option="net.ipv4.conf.default.rp_filter" l_value="1" l_grep="${l_option//./(\\.|\\/)}" a_files=() l_systemdsysctl="$(readlink -e /lib/systemd/systemd-sysctl \ || readlink -e /usr/lib/systemd/systemd-sysctl)" a_files+=("/etc/sysctl.conf") while IFS= read -r l_fname; do l_file="$(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*#\h*\/[^#…
Eigenschaften
- Betriebssysteme
- rocky-9
- Tags
- cis-convertedkernellinuxsysctl
- Referenz
- CIS Rocky Linux 9 Benchmark v3.0.0 - 3.3.1.13
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