Ensure dm-verity is enabled

MediaNivel 1Automatizadacos

Descripción

device-mapper-verity (dm-verity) kernel feature feature provides transparent integrity checking of block devices using a cryptographic digest provided by the kernel crypto API. When a dm-verity device is configured, it is expected that the caller has been authenticated in some way (cryptographic signatures, etc). After instantiation, all hashes will be verified on-demand during disk access. If they cannot be verified up to the root node of the tree, the root hash, then the I/O will fail. This should detect tampering with any data on the device and the hash data. The Container-Optimized OS root filesystem is always mounted as read-only. Additionally, its checksum is computed at build time and verified by the kernel on each boot. This mechanism prevents against attackers from "owning" the machine through permanent local changes.

Cómo se verifica

Método de auditoría: Comando de shell

shell

alt0() { command -v grep >/dev/null 2>&1 || { echo "step1: grep not installed"; return 1; }; command -v zcat >/dev/null 2>&1 || { echo "step1: zcat not installed"; return 1; }; o=$(bash -c 'zcat /proc/config.gz | grep CONFIG_DM_VERITY' 2>&1); printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- CONFIG_DM_VERITY=y || { echo step1: missing CONFIG_DM_VERITY=y; return 1; }; }; if alt0; then echo compliant; fi

Salida esperada: compliant

Cómo se corrige

Método de corrección: Guía o parche de infraestructura

An OS image update that has the dm-verity enabled kernel is required.

Propiedades

Sistemas operativos: Cualquiera
Etiquetas: container-optimized-oscos
Referencia: CIS Google Container-Optimized OS Benchmark v1.2.0 - 1.2.1 Ensure dm-verity is enabled

Verificar este host

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

shell

tmaegis scan --target cos