Ensure broadcast ICMP requests are ignored

MediaNivel 1Automatizadabottlerocket

Descripción

Setting net.ipv4.icmp_echo_ignore_broadcasts to 1 will cause the system to ignore all ICMP echo and timestamp requests to broadcast and multicast addresses. The audit reads the running value from /proc/sys. Run tmaegis on the host through the admin container root shell (sudo sheltie).

Cómo se verifica

Método de auditoría: Comando de shell

shell

bad=0
chk() { f=/proc/sys/$(printf %s "$1" | tr . /); v=$(cat "$f" 2>/dev/null) || { echo "$1: not readable"; bad=1; return; }; [ "$v" = "$2" ] || { echo "$1 = $v (expected $2)"; bad=1; }; }
chk net.ipv4.icmp_echo_ignore_broadcasts 1
[ "$bad" -eq 0 ] && echo compliant

Salida esperada: compliant

Cómo se corrige

Método de corrección: Guía o parche de infraestructura

Run the following command to set the active kernel parameter and persist the setting: # apiclient apply <<EOF [settings.kernel.sysctl] "net.ipv4.icmp_echo_ignore_broadcasts" = "1" EOF Run the following command to flush the routing cache: # sysctl -w net.ipv4.route.flush=1

Propiedades

Sistemas operativos: Cualquiera
Etiquetas: bottlerocketnetwork
Referencia: CIS Bottlerocket Benchmark v1.0.0 - 3.2.5 Ensure broadcast ICMP requests are ignored

Verificar este host

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

shell

tmaegis scan --target bottlerocket