Ensure LXD instances do not enable container nesting

MediaNivel 2Automatizadalxd

Descripción

security.nesting=true exposes /proc and /sys more widely and relaxes AppArmor so containers can run their own container runtimes, enlarging the escape surface. The audit loops over instances from "lxc list --format csv -c n" (default project) and fails if any expanded configuration sets security.nesting to a truthy value. Hosts that deliberately run Docker-in-LXD should document the exception.

Cómo se verifica

Método de auditoría: Comando de shell

shell

lxc info >/dev/null 2>&1 || exit 1
names=$(lxc list --format csv -c n 2>/dev/null) || exit 1
bad=0
for n in $names; do
  cfg=$(lxc config show --expanded "$n" 2>/dev/null) || exit 1
  if printf '%s\n' "$cfg" | grep -Eiq '^[[:space:]]*security\.nesting:[[:space:]]*"?(true|1|yes|on)"?[[:space:]]*$'; then echo "nesting: $n"; bad=1; fi
done
[ "$bad" -eq 0 ] && echo compliant

Salida esperada: compliant

Cómo se corrige

Método de corrección: Guía o parche de infraestructura

lxc config unset <instance> security.nesting (or remove it from the profile), then restart the instance. Move workloads that need nested containers to a VM instance (lxc launch --vm).

Propiedades

Sistemas operativos: Cualquiera
Etiquetas: lxdcontainersisolation
Referencia: CIS-style LXD hardening guidance - Container nesting (no CIS benchmark section; verify against your hardening standard)

Verificar este host

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

shell

tmaegis scan --target lxd --level 2