| 导读 | ssh_scan是一个面向 Linux 和 UNIX 服务器的易用的 SSH 服务参数配置和策略的扫描器程序，其思路来自Mozilla OpenSSH安全指南，这个指南为 SSH 服务参数配置提供了一个可靠的安全策略基线的建议，如加密算法（Ciphers），报文认证信息码算法（MAC），密钥交换算法（KexAlgos）和其它。 |
ssh_scan有如下好处：
- 它的依赖是最小化的，ssh_scan只引入了本地 Ruby 和 BinData 来进行它的工作，没有太多的依赖。
- 它是可移植的，你可以在其它的项目中使用ssh_scan或者将它用在自动化任务上。
- 它是易于使用的，只需要简单的将它指向一个 SSH 服务就可以获得一个该服务所支持的选项和策略状态的 JSON 格式报告。
- 它同时也是易于配置的，你可以创建适合你策略需求的策略。
建议阅读：如何在 Linux 上安装配置 OpenSSH 服务
如何在 Linux 上安装 ssh_scan有如下三种安装ssh_scan 的方式：
使用 Ruby gem 来安装运行，如下：
----------- 在 Debian/Ubuntu ----------- $ sudo apt-get install ruby gem $ sudo gem install ssh_scan ----------- 在 CentOS/RHEL ----------- # yum install ruby rubygem # gem install ssh_scan
使用docker 容器来运行，如下：
# docker pull mozilla/ssh_scan # docker run -it mozilla/ssh_scan /app/bin/ssh_scan -t github.com
使用源码安装运行，如下：
# git clone https://github.com/mozilla/ssh_scan.git # cd ssh_scan # gpg2 --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3 # curl -sSL https://get.rvm.io | bash -s stable # rvm install 2.3.1 # rvm use 2.3.1 # gem install bundler # bundle install # ./bin/ssh_scan如何在 Linux 上使用 ssh_scan
使用ssh_scan的语法如下：
$ ssh_scan -t ip地址 $ ssh_scan -t 主机名
举个例子来扫描 192.168.43.198 这台服务器的 SSH 配置和策略，键入：
$ ssh_scan -t 192.168.43.198
注意你同时也可以像下方展示的给-t选项传入一个[IP地址/地址段/主机名]：
Linux Security Scanner
下载
Linux 安全审计工具，检查 SSH 配置、开放/监听端口、防火墙规则（ufw/iptables/nftables）、失败登录尝试、sudoers 权限...
$ ssh_scan -t 192.168.43.198,200,205 $ ssh_scan -t test.tecmint.lan
输出示例：
I, [2017-05-09T10:36:17.913644 #7145] INFO -- : You're using the latest version of ssh_scan 0.0.19
[
{
"ssh_scan_version": "0.0.19",
"ip": "192.168.43.198",
"port": 22,
"server_banner": "SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.1",
"ssh_version": 2.0,
"os": "ubuntu",
"os_cpe": "o:canonical:ubuntu:16.04",
"ssh_lib": "openssh",
"ssh_lib_cpe": "a:openssh:openssh:7.2p2",
"cookie": "68b17bcca652eeaf153ed18877770a38",
"key_algorithms": [
"[email protected]",
"ecdh-sha2-nistp256",
"ecdh-sha2-nistp384",
"ecdh-sha2-nistp521",
"diffie-hellman-group-exchange-sha256",
"diffie-hellman-group14-sha1"
],
"server_host_key_algorithms": [
"ssh-rsa",
"rsa-sha2-512",
"rsa-sha2-256",
"ecdsa-sha2-nistp256",
"ssh-ed25519"
],
"encryption_algorithms_client_to_server": [
"[email protected]",
"aes128-ctr",
"aes192-ctr",
"aes256-ctr",
"[email protected]",
"[email protected]"
],
"encryption_algorithms_server_to_client": [
"[email protected]",
"aes128-ctr",
"aes192-ctr",
"aes256-ctr",
"[email protected]",
"[email protected]"
],
"mac_algorithms_client_to_server": [
"[email protected]",
"[email protected]",
"[email protected]",
"[email protected]",
"[email protected]",
"[email protected]",
"[email protected]",
"hmac-sha2-256",
"hmac-sha2-512",
"hmac-sha1"
],
"mac_algorithms_server_to_client": [
"[email protected]",
"[email protected]",
"[email protected]",
"[email protected]",
"[email protected]",
"[email protected]",
"[email protected]",
"hmac-sha2-256",
"hmac-sha2-512",
"hmac-sha1"
],
"compression_algorithms_client_to_server": [
"none",
"[email protected]"
],
"compression_algorithms_server_to_client": [
"none",
"[email protected]"
],
"languages_client_to_server": [
],
"languages_server_to_client": [
],
"hostname": "tecmint",
"auth_methods": [
"publickey",
"password"
],
"fingerprints": {
"rsa": {
"known_bad": "false",
"md5": "0e:d0:d7:11:f0:9b:f8:33:9c:ab:26:77:e5:66:9e:f4",
"sha1": "fc:8d:d5:a1:bf:52:48:a6:7e:f9:a6:2f:af:ca:e2:f0:3a:9a:b7:fa",
"sha256": "ff:00:b4:a4:40:05:19:27:7c:33:aa:db:a6:96:32:88:8e:bf:05:a1:81:c0:a4:a8:16:01:01:0b:20:37:81:11"
}
},
"start_time": "2017-05-09 10:36:17 +0300",
"end_time": "2017-05-09 10:36:18 +0300",
"scan_duration_seconds": 0.221573169,
"duplicate_host_key_ips": [
],
"compliance": {
"policy": "Mozilla Modern",
"compliant": false,
"recommendations": [
"Remove these Key Exchange Algos: diffie-hellman-group14-sha1",
"Remove these MAC Algos: [email protected], [email protected], [email protected], hmac-sha1",
"Remove these Authentication Methods: password"
],
"references": [
"https://wiki.mozilla.org/Security/Guidelines/OpenSSH"
]
}
}
]
你可以使用-p选项来指定不同的端口，-L选项来开启日志记录配合-V选项来指定日志级别：
$ ssh_scan -t 192.168.43.198 -p 22222 -L ssh-scan.log -V INFO
另外，可以使用-P或--policy选项来指定一个策略文件（默认是 Mozilla Modern）：
$ ssh_scan -t 192.168.43.198 -L ssh-scan.log -V INFO -P /path/to/custom/policy/file
ssh_scan 使用帮助与其它示例：
$ ssh_scan -h
输出示例：
ssh_scan v0.0.17 (https://github.com/mozilla/ssh_scan) Usage: ssh_scan [options] -t, --target [IP/Range/Hostname] IP/Ranges/Hostname to scan -f, --file [FilePath] File Path of the file containing IP/Range/Hostnames to scan -T, --timeout [seconds] Timeout per connect after which ssh_scan gives up on the host -L, --logger [Log File Path] Enable logger -O, --from_json [FilePath] File to read JSON output from -o, --output [FilePath] File to write JSON output to -p, --port [PORT] Port (Default: 22) -P, --policy [FILE] Custom policy file (Default: Mozilla Modern) --threads [NUMBER] Number of worker threads (Default: 5) --fingerprint-db [FILE] File location of fingerprint database (Default: ./fingerprints.db) --suppress-update-status Do not check for updates -u, --unit-test [FILE] Throw appropriate exit codes based on compliance status -V [STD_LOGGING_LEVEL], --verbosity -v, --version Display just version info -h, --help Show this message Examples: ssh_scan -t 192.168.1.1 ssh_scan -t server.example.com ssh_scan -t ::1 ssh_scan -t ::1 -T 5 ssh_scan -f hosts.txt ssh_scan -o output.json ssh_scan -O output.json -o rescan_output.json ssh_scan -t 192.168.1.1 -p 22222 ssh_scan -t 192.168.1.1 -p 22222 -L output.log -V INFO ssh_scan -t 192.168.1.1 -P custom_policy.yml ssh_scan -t 192.168.1.1 --unit-test -P custom_policy.yml
SSH 服务器相关参考阅读：
- 使用 SSH Keygen（ssh-keygen）五步实现 SSH 免密登录
- 安全 SSH 服务器的 5 个最佳实践
- 使用 Chroot 来限制 SSH 用户进入某些目录
- 如何配置 SSH 连接来简化远程登录
