Ensure only strong ciphers are used

보통레벨 1자동linux

설명

This variable limits the ciphers that SSH can use during communication.

점검 방법

감사 방식: 셸 명령

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=$(bash -c 'sshd -T | grep ciphers' 2>&1); printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Week Ciphers:' || { echo step1: missing 'Week Ciphers:'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 3des-cbc || { echo step1: missing 3des-cbc; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- aes128-cbc || { echo step1: missing aes128-cbc; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- aes192-cbc || { echo step1: missing aes192-cbc; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- aes256-cbc || { echo step1: missing aes256-cbc; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- arcfour || { echo step1: missing arcfour; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- arcfour128 || { echo step1: missing arcfour128; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- arcfour256 || { echo step1: missing arcfour256; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- blowfish-cbc || { echo step1: missing blowfish-cbc; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- cast128-cbc || { echo step1: missing cast128-cbc; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- rijndael-cbc@lysator.liu.se || { echo step1: missing rijndael-cbc@lysator.liu.se; return 1; }; }; if alt0; then echo compliant; fi

예상 출력: compliant

조치 방법

조치 방식: 가이드 또는 인프라 패치

Edit the /etc/ssh/sshd_config file add/modify the Ciphers line to contain a comma separated list of the site approved ciphers Example: Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128- gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr Restart sshd : systemctl restart sshd

속성

운영 체제: alinux-2
태그: cis-convertedlinux
참고 자료: CIS Aliyun Linux 2 Benchmark v1.0.0 ARCHIVE - 5.2.17

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