TMA-FREEBSD-4.2.11

Ensure sshd KexAlgorithms is configured

높음레벨 1자동freebsd

설명

Key exchange is any cryptography method that exchanges cryptographic keys between two parties, allowing the use of a cryptographic algorithm. If the sender and receiver wish to exchange encrypted messages, each must be equipped to encrypt messages to be sent and decrypt messages received. Key exchange methods that are considered weak should be removed. A key exchange method may be weak because too few bits are used or the hashing algorithm is considered too weak. Using weak algorithms could expose connections to man-in-the- middle attacks. Audit: the effective `kexalgorithms` 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' "$out" | grep -i '^kexalgorithms '); [ -n "$line" ] || exit 1; printf '%s\n' "$line" | grep -Eiq -- '(^|[ ,])(diffie-hellman-group1-sha1|diffie-hellman-group14-sha1|diffie-hellman-group-exchange-sha1)(,|$)' && 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 KexAlgorithms line to contain a comma-separated list of the site unapproved (weak) KexAlgorithms preceded with a - above any Include entries: Example: KexAlgorithms -diffie-hellman-group1-sha1,diffie-hellman-group14-sha1,diffie- hellman-group-exchange-sha1

속성

운영 체제: 모두
태그: freebsdssh
참고 자료: CIS FreeBSD 14 Benchmark v1.0.1 - 4.2.11 Ensure sshd KexAlgorithms is configured

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shell

tmaegis scan --target freebsd