Ensure SSH AllowTcpForwarding is disabled

낮음레벨 2자동cos

설명

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

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=$(bash -c 'sshd -T | grep -i allowtcpforwarding' 2>&1); printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'AllowTcpForwarding no' || { echo step1: missing 'AllowTcpForwarding no'; return 1; }; }; if alt0; then echo compliant; fi

예상 출력: compliant

조치 방법

조치 방식: 가이드 또는 인프라 패치

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

속성

운영 체제: 모두
태그: container-optimized-oscosssh
참고 자료: CIS Google Container-Optimized OS Benchmark v1.2.0 - 5.1.20 Ensure SSH AllowTcpForwarding is disabled

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shell

tmaegis scan --target cos --level 2