Ensure kernel.yama.ptrace_scope is configured

MédiaNível 1Automatizadalinux

Descrição

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

Como é verificado

Método de auditoria: Comando 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

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 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…

Propriedades

Sistemas operacionais: almalinux-8
Tags: cis-convertedkernellinuxsysctl
Referência: CIS AlmaLinux OS 8 Benchmark v4.0.0 - 1.5.7

Verificar este host

Execute isto em uma máquina que você tenha permissão para auditar. A varredura é somente leitura.

shell

tmaegis scan --target linux