Ensure SSH AllowTcpForwarding is disabled

低级别 2自动化cos

说明

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

检查方式

审计方法: Shell 命令

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

预期输出: compliant

修复方式

修复方法: 操作指南或基础设施补丁

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

属性

操作系统: 任意
标签: container-optimized-oscosssh
参考: CIS Google Container-Optimized OS Benchmark v1.2.0 - 5.1.20 Ensure SSH AllowTcpForwarding is disabled

检查本机

请在您有权审计的机器上运行此命令。扫描为只读操作。

shell

tmaegis scan --target cos --level 2