TMA-COS-1.2.1

Ensure dm-verity is enabled

中レベル 1自動cos

説明

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.

チェック方法

監査方法: シェルコマンド

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

期待される出力: compliant

修正方法

修正方法: ガイダンスまたは IaC パッチ

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

プロパティ

オペレーティングシステム: すべて
タグ: container-optimized-oscos
参照: CIS Google Container-Optimized OS Benchmark v1.2.0 - 1.2.1 Ensure dm-verity is enabled

このホストをチェック

監査が許可されているマシンで実行してください。スキャンは読み取り専用です。

shell

tmaegis scan --target cos