利用lynis如何进行linux漏洞扫描详解

前言

lynis 是一款运行在 Unix/Linux 平台上的基于主机的、开源的安全审计软件。Lynis是针对Unix/Linux的安全检查工具，可以发现潜在的安全威胁。这个工具覆盖可疑文件监测、漏洞、恶意程序扫描、配置错误等。下面一起来看看使用lynis进行linux漏洞扫描的相关内容吧

安装lynis

在 archlinux 上可以直接通过 pacman 来安装

sudo pacman -S lynis --noconfirm

resolving dependencies...
looking for conflicting packages...

Packages (1) lynis-2.6.4-1

Total Installed Size: 1.35 MiB
Net Upgrade Size:  0.00 MiB

:: Proceed with installation? [Y/n]
(0/1) checking keys in keyring      [----------------------] 0％
(1/1) checking keys in keyring      [######################] 100％
(0/1) checking package integrity     [----------------------] 0％
(1/1) checking package integrity     [######################] 100％
(0/1) loading package files      [----------------------] 0％
(1/1) loading package files      [######################] 100％
(0/1) checking for file conflicts     [----------------------] 0％
(1/1) checking for file conflicts     [######################] 100％
(0/1) checking available disk space    [----------------------] 0％
(1/1) checking available disk space    [######################] 100％
:: Processing package changes...
(1/1) reinstalling lynis       [----------------------] 0％
(1/1) reinstalling lynis       [######################] 100％
:: Running post-transaction hooks...
(1/2) Reloading system manager configuration...
(2/2) Arming ConditionNeedsUpdate...

使用lynis进行主机扫描

首先让我们不带任何参数运行 lynis, 这会列出 lynis 支持的那些参数

[lujun9972@T520 linux和它的小伙伴]$ lynis

[ Lynis 2.6.4 ]

################################################################################
Lynis comes with ABSOLUTELY NO WARRANTY. This is free software, and you are
welcome to redistribute it under the terms of the GNU General Public License.
See the LICENSE file for details about using this software.

2007-2018, CISOfy - https://cisofy.com/lynis/
Enterprise support available (compliance, plugins, interface and tools)
################################################################################

[+] Initializing program
------------------------------------

Usage: lynis command [options]

Command:

audit
 audit system     : Perform local security scan
 audit system remote <host> : Remote security scan
 audit dockerfile <file>  : Analyze Dockerfile

show
 show       : Show all commands
 show version     : Show Lynis version
 show help      : Show help

update
 update info     : Show update details

Options:

--no-log       : Don't create a log file
--pentest       : Non-privileged scan (useful for pentest)
--profile <profile>    : Scan the system with the given profile file
--quick (-Q)      : Quick mode, don't wait for user input

Layout options
--no-colors      : Don't use colors in output
--quiet (-q)      : No output
--reverse-colors     : Optimize color display for light backgrounds

Misc options
--debug       : Debug logging to screen
--view-manpage (--man)   : View man page
--verbose       : Show more details on screen
--version (-V)     : Display version number and quit

Enterprise options
--plugindir <path>    : Define path of available plugins
--upload       : Upload data to central node

More options available. Run '/usr/bin/lynis show options', or use the man page.

No command provided. Exiting..

从上面可以看出，使用 lynis 进行主机扫描很简单，只需要带上参数 audit system 即可。 Lynis在审计的过程中,会进行多种类似的测试,在审计过程中会将各种测试结果、调试信息、和对系统的加固建议都被写到 stdin 。 我们可以执行下面命令来跳过检查过程,直接截取最后的扫描建议来看。

sudo lynis audit system |sed '1,/Results/d'

lynis将扫描的内容分成几大类，可以通过 show groups 参数来获取类别

lynis show groups

accounting
authentication
banners
boot_services
containers
crypto
databases
dns
file_integrity
file_permissions
filesystems
firewalls
hardening
homedirs
insecure_services
kernel
kernel_hardening
ldap
logging
mac_frameworks
mail_messaging
malware
memory_processes
nameservices
networking
php
ports_packages
printers_spools
scheduling
shells
snmp
squid
ssh
storage
storage_nfs
system_integrity
time
tooling
usb
virtualization
webservers

若指向扫描某几类的内容，则可以通过 –tests-from-group 参数来指定。

比如我只想扫描 shells 和 networking 方面的内容，则可以执行

sudo lynis --tests-from-group "shells networking" --no-colors

[ Lynis 2.6.4 ]

################################################################################
Lynis comes with ABSOLUTELY NO WARRANTY. This is free software, and you are
welcome to redistribute it under the terms of the GNU General Public License.
See the LICENSE file for details about using this software.

2007-2018, CISOfy - https://cisofy.com/lynis/
Enterprise support available (compliance, plugins, interface and tools)
################################################################################

[+] Initializing program
------------------------------------
- Detecting OS...  [ DONE ]
- Checking profiles... [ DONE ]
- Detecting language and localization [ zh ]
Notice: no language file found for 'zh' (tried: /usr/share/lynis/db/languages/zh)

---------------------------------------------------
Program version:   2.6.4
Operating system:   Linux
Operating system name:  Arch Linux
Operating system version: Rolling release
Kernel version:   4.16.13
Hardware platform:   x86_64
Hostname:     T520
---------------------------------------------------
Profiles:     /etc/lynis/default.prf
Log file:     /var/log/lynis.log
Report file:    /var/log/lynis-report.dat
Report version:   1.0
Plugin directory:   /usr/share/lynis/plugins
---------------------------------------------------
Auditor:     [Not Specified]
Language:     zh
Test category:    all
Test group:    shells networking
---------------------------------------------------
- Program update status...  [ NO UPDATE ]

[+] System Tools
------------------------------------
- Scanning available tools...
- Checking system binaries...

[+] Plugins (phase 1)
------------------------------------
Note: plugins have more extensive tests and may take several minutes to complete
 
- Plugins enabled [ NONE ]

[+] Shells
------------------------------------
- Checking shells from /etc/shells
Result: found 5 shells (valid shells: 5).
- Session timeout settings/tools [ NONE ]
- Checking default umask values
- Checking default umask in /etc/bash.bashrc [ NONE ]
- Checking default umask in /etc/profile [ WEAK ]

[+] Networking
------------------------------------
- Checking IPv6 configuration [ ENABLED ]
Configuration method [ AUTO ]
IPv6 only [ NO ]
- Checking configured nameservers
- Testing nameservers
Nameserver: 202.96.134.33 [ SKIPPED ]
Nameserver: 202.96.128.86 [ SKIPPED ]
- Minimal of 2 responsive nameservers [ SKIPPED ]
- Getting listening ports (TCP/UDP) [ DONE ]
* Found 11 ports
- Checking status DHCP client [ RUNNING ]
- Checking for ARP monitoring software [ NOT FOUND ]

[+] Custom Tests
------------------------------------
- Running custom tests...  [ NONE ]

[+] Plugins (phase 2)
------------------------------------

================================================================================

-[ Lynis 2.6.4 Results ]-

Great, no warnings

Suggestions (1):
----------------------------
* Consider running ARP monitoring software (arpwatch,arpon) [NETW-3032]

https://cisofy.com/controls/NETW-3032/

Follow-up:
----------------------------
- Show details of a test (lynis show details TEST-ID)
- Check the logfile for all details (less /var/log/lynis.log)
- Read security controls texts (https://cisofy.com)
- Use --upload to upload data to central system (Lynis Enterprise users)

================================================================================

Lynis security scan details:

Hardening index : 33 [######    ]
Tests performed : 13
Plugins enabled : 0

Components:
- Firewall    [X]
- Malware scanner  [X]

Lynis Modules:
- Compliance Status  [?]
- Security Audit   [V]
- Vulnerability Scan  [V]

Files:
- Test and debug information  : /var/log/lynis.log
- Report data      : /var/log/lynis-report.dat

================================================================================

Lynis 2.6.4

Auditing, system hardening, and compliance for UNIX-based systems
(Linux, macOS, BSD, and others)

2007-2018, CISOfy - https://cisofy.com/lynis/
Enterprise support available (compliance, plugins, interface and tools)

================================================================================

[TIP]: Enhance Lynis audits by adding your settings to custom.prf (see /etc/lynis/default.prf for all settings)

查看详细说明

在查看审计结果时,你可以通过 show details 参数来获取关于某条警告/建议的详细说明。其对应的命令形式为:

lynis show details ${test_id}

比如，上面图中有一个建议

* Consider running ARP monitoring software (arpwatch,arpon) [NETW-3032]

我们可以运行命令：

sudo lynis show details NETW-3032

2018-06-08 18:18:01 Performing test ID NETW-3032 (Checking for ARP monitoring software)
2018-06-08 18:18:01 IsRunning: process 'arpwatch' not found
2018-06-08 18:18:01 IsRunning: process 'arpon' not found
2018-06-08 18:18:01 Suggestion: Consider running ARP monitoring software (arpwatch,arpon) [test:NETW-3032] [details:-] [solution:-]
2018-06-08 18:18:01 Checking permissions of /usr/share/lynis/include/tests_printers_spools
2018-06-08 18:18:01 File permissions are OK
2018-06-08 18:18:01 ===---------------------------------------------------------------===

查看日志文件

lynis在审计完成后会将详细的信息记录在 /var/log/lynis.log 中.

sudo tail /var/log/lynis.log

2018-06-08 17:59:46 ================================================================================
2018-06-08 17:59:46 Lynis 2.6.4
2018-06-08 17:59:46 2007-2018, CISOfy - https://cisofy.com/lynis/
2018-06-08 17:59:46 Enterprise support available (compliance, plugins, interface and tools)
2018-06-08 17:59:46 Program ended successfully
2018-06-08 17:59:46 ================================================================================
2018-06-08 17:59:46 PID file removed (/var/run/lynis.pid)
2018-06-08 17:59:46 Temporary files: /tmp/lynis.sGxCR0hSPz
2018-06-08 17:59:46 Action: removing temporary file /tmp/lynis.sGxCR0hSPz
2018-06-08 17:59:46 Lynis ended successfully.

同时将报告数据被保存到 /var/log/lynis-report.dat 中.

sudo tail /var/log/lynis-report.dat

另外需要注意的是，每次审计都会覆盖原日志文件.

检查更新

审计软件需要随时进行更新从而得到最新的建议和信息，我们可以使用 update info 参数来检查更新:

lynis update info --no-colors

== Lynis ==

Version   : 2.6.4
Status    : Up-to-date
Release date  : 2018-05-02
Update location : https://cisofy.com/lynis/

2007-2018, CISOfy - https://cisofy.com/lynis/

自定义lynis安全审计策略

lynis的配置信息以 .prf 文件的格式保存在 /etc/lynis 目录中。 其中，默认lynis自带一个名为 default.prf 的默认配置文件。

不过我们无需直接修改这个默认的配置文件，只需要新增一个 custom.prf 文件将自定义的信息加入其中就可以了。

关于配置文件中各配置项的意义，在 default.prf 中都有相应的注释说明,这里就不详述了。

想了解lynis的更多信息，可以访问它的官网.

来源：https://lujun9972.github.io/blog/2018/06/08/使用lynis进行linux漏洞扫描/