Ensure unprivileged eBPF is disabled

AltaNivel 1Automatizadaazure-container-linux

Descripción

eBPF (extended Berkeley Packet Filter) allows programs to be loaded and executed within kernel context. Unprivileged users should not be able to load eBPF programs. On Azure Container Linux the kernel parameter kernel.unprivileged_bpf_disabled is set to 1.

Cómo se verifica

Método de auditoría: Comando de 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.unprivileged_bpf_disabled 1; then echo compliant; fi

Salida esperada: compliant

Cómo se corrige

Método de corrección: Guía o parche de infraestructura

Set the following parameter in /etc/sysctl.conf or a file in /etc/sysctl.d/ ending in .conf: kernel.unprivileged_bpf_disabled = 1 Example: # printf '%s\n' "kernel.unprivileged_bpf_disabled = 1" >> /etc/sysctl.d/60- kernel_sysctl.conf Run the following command to set the active kernel parameter: # sysctl -w kernel.unprivileged_bpf_disabled=1

Propiedades

Sistemas operativos: Cualquiera
Etiquetas: azure-container-linuxcis-convertedkernelsysctl
Referencia: CIS Azure Container Linux Benchmark v1.0.0 - 1.4.8 Ensure unprivileged eBPF is disabled

Verificar este host

Ejecute esto en un equipo que tenga permiso para auditar. El escaneo es de solo lectura.

shell

tmaegis scan --target azure-container-linux