TMA-COS-5.1.20

Ensure SSH AllowTcpForwarding is disabled

低レベル 2自動cos

説明

SSH port forwarding is a mechanism in SSH for tunneling application ports from the client to the server, or servers to clients. It can be used for adding encryption to legacy applications, going through firewalls, and some system administrators and IT professionals use it for opening backdoors into the internal network from their home machines Leaving port forwarding enabled can expose the organization to security risks and back- doors. SSH connections are protected with strong encryption. This makes their contents invisible to most deployed network monitoring and traffic filtering solutions. This invisibility carries considerable risk potential if it is used for malicious purposes such as data exfiltration. Cybercriminals or malware could exploit SSH to hide their unauthorized communications, or to exfiltrate stolen data from the target network

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 sshd >/dev/null 2>&1 || { echo "step1: sshd not installed"; return 1; }; o=$(bash -c 'sshd -T | grep -i allowtcpforwarding' 2>&1); printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'AllowTcpForwarding no' || { echo step1: missing 'AllowTcpForwarding no'; 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

Edit the /etc/ssh/sshd_config file to set the parameter as follows: AllowTcpForwarding no

プロパティ

オペレーティングシステム: すべて
タグ: container-optimized-oscosssh
参照: CIS Google Container-Optimized OS Benchmark v1.2.0 - 5.1.20 Ensure SSH AllowTcpForwarding is disabled

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 --level 2