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TMA-ROCKY9-3.3.1.17

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

中级别 1自动化linux

说明

When enabled, this feature logs packets with un-routable source addresses to the kernel log. net.ipv4.conf.default.log_martians controls if IPv4 packets with un-routable source addresses on a newly added network interface is logged to the kernel log. More information about the kernel parameter configuration files, their location, and load preference is available in the "Configure Network Kernel Parameters" section overview.

检查方式

审计方法: Shell 命令

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.log_martians 1; then echo compliant; fi
预期输出
compliant

修复方式

修复方法: 操作指南或基础设施补丁

1. Review all files being used by systemd sysctl and comment out or remove all net.ipv4.conf.default.log_martians lines that are not net.ipv4.conf.default.log_martians=1. Example script: #!/usr/bin/env bash { l_option="net.ipv4.conf.default.log_martians" 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*…

属性

操作系统
rocky-9
标签
cis-convertedkernellinuxsysctl
参考
CIS Rocky Linux 9 Benchmark v3.0.0 - 3.3.1.17

检查本机

请在您有权审计的机器上运行此命令。扫描为只读操作。

shell
tmaegis scan --target linux