SSH Unrestricted Access from Non-Whitelisted IPs

漏洞信息

漏洞名称： SSH Unrestricted Access from Non-Whitelisted IPs

漏洞类型： 未授权访问

漏洞等级： 中危

漏洞描述： 受影响的产品是SSH（Secure Shell），一种广泛使用的网络协议，用于安全地访问远程计算机。SSH在企业和个人环境中都非常常见，用于远程服务器管理、文件传输等。该漏洞的具体表现为SSH服务未限制访问IP，允许任何来源的IP地址连接，这大大增加了未授权访问和暴力破解攻击的风险。漏洞的技术根源在于SSH服务的配置文件中未正确设置ListenAddress参数，或者该参数被注释掉，导致服务监听所有网络接口上的连接请求。这种配置问题使得攻击者可以从任何IP地址尝试连接SSH服务，进行未授权访问或暴力破解攻击，从而可能获取系统权限，导致数据泄露或服务中断。由于SSH服务通常运行在高权限账户下，一旦被攻破，攻击者可以完全控制系统，造成严重的安全后果。修复建议包括在/etc/ssh/sshd_config配置文件中设置ListenAddress参数，仅允许来自信任IP地址的连接，并重启SSH服务以应用更改。

产品名称： SSH

来源： https://github.com/projectdiscovery/nuclei-templates/blob/804d1df949d5fbbfdee11564a2df65b6836a8d60/javascript%2Faudit%2Fssh%2Fssh-unrestricted-nonwhitelist.yaml

类型： projectdiscovery/nuclei-templates:github issues

POC详情

id: ssh-unrestricted-nonwhitelist

info:
  name: Unrestricted SSH Access from Non-Whitelisted IPs
  author: pussycat0x
  severity: unknown
  description: |
    SSH access is not restricted to specific IP addresses, allowing connections from any source. This increases the risk of unauthorized access and brute-force attacks.
  remediation: |
    Restrict SSH to specific IPs in /etc/ssh/sshd_config by setting ListenAddress <trusted-IP> and restarting the SSH service.
  reference:
    - https://vishalraj82.medium.com/hardening-openssh-security-37f5d634015f
    - https://www.cyberciti.biz/tips/howto-openssh-sshd-listen-multiple-ip-address.html
  metadata:
    verified: true
  tags: audit,config,ssh,auth

javascript:
  - pre-condition: |
      isPortOpen(Host,Port);
    code: |
      var m = require("nuclei/ssh");
      var c = m.SSHClient();
      c.Connect(Host,Port,User,Pass);
      const sshConfig = c.Run('cat /etc/ssh/sshd_config')
      sshConfig
      let result = "";
      if (sshConfig.includes('#ListenAddress') && !sshConfig.includes('ListenAddress  ')){
      result += "SSH access restriction not enforced";
      }
      else{
      exit();
      }
      result

    args:
      Host: "{{Host}}"
      Port: "22"
      User: "{{usernames}}"
      Pass: "{{passwords}}"

    matchers:
      - type: dsl
        dsl:
          - "success == true"

    extractors:
      - type: dsl
        dsl:
          - response
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