Ensure ICMP redirects are not accepted

BajaNivel 2Automatizadabottlerocket

Descripción

ICMP redirect messages are packets that convey routing information and tell your host (acting as a router) to send packets via an alternate path. It is a way of allowing an outside routing device to update your system routing tables. The audit reads the running values from /proc/sys (IPv6 keys only when IPv6 is enabled). 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 $2)"; bad=1; }; }
chk net.ipv4.conf.all.accept_redirects 0
chk net.ipv4.conf.default.accept_redirects 0
[ -d /proc/sys/net/ipv6 ] && chk net.ipv6.conf.all.accept_redirects 0
[ -d /proc/sys/net/ipv6 ] && chk net.ipv6.conf.default.accept_redirects 0
[ "$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 parameters and persist the settings: # apiclient apply <<EOF [settings.kernel.sysctl] "net.ipv4.conf.all.accept_redirects" = "0" "net.ipv4.conf.default.accept_redirects" = "0" "net.ipv6.conf.all.accept_redirects" = "0" "net.ipv6.conf.default.accept_redirects" = "0" EOF Run the following commands to flush the routing caches: # sysctl -w net.ipv4.route.flush=1 # sysctl -w net.ipv6.route.flush=1

Propiedades

Sistemas operativos: Cualquiera
Etiquetas: bottlerocketnetwork
Referencia: CIS Bottlerocket Benchmark v1.0.0 - 3.2.2 Ensure ICMP redirects are not accepted

Verificar este host

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

shell

tmaegis scan --target bottlerocket --level 2