Ensure sshd MACs are configured

높음레벨 1자동freebsd

설명

This variable limits the types of MAC algorithms that SSH can use during communication. Notes: Some organizations may have stricter requirements for approved MACs. Ensure that MACs used are in compliance with site policy. The only "strong" MACs currently FIPS 140-2 approved are: o HMAC-SHA1 o HMAC-SHA2-256 o HMAC-SHA2-384 o HMAC-SHA2-512 Audit: the effective `macs` list from `sshd -T` must not contain any weak algorithm listed by CIS.

점검 방법

감사 방식: 셸 명령

shell

command -v sshd >/dev/null 2>&1 || exit 1; out=$(sshd -T 2>/dev/null) || exit 1; line=$(printf '%s\n' "$out" | grep -i '^macs '); [ -n "$line" ] || exit 1; printf '%s\n' "$line" | grep -Eiq -- '(^|[ ,])(hmac-md5|hmac-md5-96|hmac-ripemd160|hmac-sha1-96|umac-64@openssh\.com|hmac-md5-etm@openssh\.com|hmac-md5-96-etm@openssh\.com|hmac-ripemd160-etm@openssh\.com|hmac-sha1-96-etm@openssh\.com|umac-64-etm@openssh\.com|umac-128-etm@openssh\.com)(,|$)' && echo "weak: $line" || echo compliant

예상 출력: compliant

조치 방법

조치 방식: 가이드 또는 인프라 패치

Edit the /etc/ssh/sshd_config file and add/modify the MACs line to contain a comma separated list of the site unapproved (weak) MACs preceded with a - above any Include entries: Example: MACs -hmac-md5,hmac-md5-96,hmac-ripemd160,hmac-sha1-96,umac- 64@openssh.com,hmac-md5-etm@openssh.com,hmac-md5-96-etm@openssh.com,hmac- ripemd160-etm@openssh.com,hmac-sha1-96-etm@openssh.com,umac-64- etm@openssh.com

속성

운영 체제: 모두
태그: freebsdssh
참고 자료: CIS FreeBSD 14 Benchmark v1.0.1 - 4.2.14 Ensure sshd MACs are configured

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shell

tmaegis scan --target freebsd