TMA-COS-1.1.2

Ensure /tmp is configured

中レベル 1自動cos

説明

The /tmp directory is a world-writable directory used for temporary storage by all users and some applications. Making /tmp its own file system allows an administrator to set the noexec option on the mount, making /tmp useless for an attacker to install executable code. It would also prevent an attacker from establishing a hardlink to a system setuid program and wait for it to be updated. Once the program was updated, the hardlink would be broken and the attacker would have his own copy of the program. If the program happened to have a security vulnerability, the attacker could continue to exploit the known flaw. This can be accomplished by either mounting tmpfs to /tmp, or creating a separate partition for /tmp.

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 mount >/dev/null 2>&1 || { echo "step1: mount not installed"; return 1; }; o=$(bash -c 'mount | grep -E '"'"'\s/tmp\s'"'"'' 2>&1); printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'tmpfs on /tmp type tmpfs (rw,nosuid,nodev,noexec,relatime)' || { echo step1: missing 'tmpfs on /tmp type tmpfs (rw,nosuid,nodev,noexec,relatime)'; return 1; }; command -v systemctl >/dev/null 2>&1 || { echo "step2: systemctl not installed"; return 1; }; o=$(bash -c 'systemctl is-enabled tmp.mount' 2>&1); printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- static || { echo step2: missing static; 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

Run the following commands to configure mount options systemctl edit tmp.mount Edit the file to define the options that needs to be set. For example: [Mount] Options= Options=mode=1777,strictatime,noexec,nodev,nosuid Restart the tmp.mount systemctl daemon-reload # might be optional systemctl restart tmp.mount /etc is stateless on Container-Optimized OS. Therefore, /etc cannot be used to make these changes persistent across reboots. The steps mentioned above needs to be performed after every boot.

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 - 1.1.2 Ensure /tmp is configured

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