Ensure kernel.yama.ptrace_scope is configured

MoyenneNiveau 1Automatiséelinux

Description

The ptrace() system call provides a means by which one process (the "tracer") may observe and control the execution of another process (the "tracee"), and examine and change the tracee's memory and registers. The sysctl settings (writable only with CAP_SYS_PTRACE) are: • 0 - classic ptrace permissions: a process can PTRACE_ATTACH to any other process running under the same uid, as long as it is dumpable (i.e. did not transition uids, start privileged, or have called prctl(PR_SET_DUMPABLE...) already). Similarly, PTRACE_TRACEME is unchanged. • 1 - restricted ptrace: a process must have a predef

Méthode de vérification

Méthode d'audit: Commande shell

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 kernel.yama.ptrace_scope '1 2 3'; then echo compliant; fi

Sortie attendue: compliant

Méthode de correction

Méthode de correction: Recommandation ou correctif d'infrastructure

1. Review all files being used by systemd sysctl and comment out or remove all kernel.yama.ptrace_scope lines that are not kernel.yama.ptrace_scope=1, kernel.yama.ptrace_scope=2, or kernel.yama.ptrace_scope=3. Example script: #!/usr/bin/env bash { l_option="kernel.yama.ptrace_scope" l_value="(1|2|3)" 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="$(re…

Propriétés

Systèmes d'exploitation: almalinux-8
Étiquettes: cis-convertedkernellinuxsysctl
Référence: CIS AlmaLinux OS 8 Benchmark v4.0.0 - 1.5.7

Vérifier cet hôte

Exécutez cette commande sur une machine que vous êtes autorisé à auditer. L'analyse est en lecture seule.

shell

tmaegis scan --target linux