TMA-AIX-4.6.3.11

Ensure sshd MACs are configured

높음레벨 1자동aix

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 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 -: 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,umac-128-etm@openssh.com - IF - CVE-2023-48795 has not been reviewed and addressed, the following etm MACs should be added to the exclude list: hmac-sha1-etm@openssh.com,hmac-sha2-256- etm@openssh.com,hmac-sha2-512-etm@openssh.com Re-cycle the sshd daemon to pick up the configuration changes: stopsrc -s sshd startsrc -s sshd

속성

운영 체제: 모두
태그: aixssh
참고 자료: CIS IBM AIX 7 Benchmark v1.2.0 - 4.6.3.11 Ensure sshd MACs are configured

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shell

tmaegis scan --target aix