Lynis 2.3.3 - Security Auditing Tool for Unix/Linux Systems

Wednesday, August 24, 2016

We are excited to announce this major release of auditing tool Lynis. Several big changes have been made to core functions of Lynis. These changes are the next of simplification improvements we made. There is a risk of breaking your existing configuration.

Lynis is an open source security auditing tool. Used by system administrators, security professionals, and auditors, to evaluate the security defenses of their Linux and UNIX-based systems. It runs on the host itself, so it performs more extensive security scans than vulnerability scanners.

Supported operating systems

The tool has almost no dependencies, therefore it runs on almost all Unix based systems and versions, including:
  • AIX
  • FreeBSD
  • HP-UX
  • Linux
  • Mac OS
  • NetBSD
  • OpenBSD
  • Solaris
  • and others
It even runs on systems like the Raspberry Pi and several storage devices!

Installation optional

Lynis is light-weight and easy to use. Installation is optional: just copy it to a system, and use "./lynis audit system" to start the security scan. It is written in shell script and released as open source software (GPL). 

How it works

Lynis performs hundreds of individual tests, to determine the security state of the system. The security scan itself consists of performing a set of steps, from initialization the program, up to the report.

  1. Determine operating system
  2. Search for available tools and utilities
  3. Check for Lynis update
  4. Run tests from enabled plugins
  5. Run security tests per category
  6. Report status of security scan
Besides the data displayed on screen, all technical details about the scan are stored in a log file. Any findings (warnings, suggestions, data collection) are stored in a report file.

Opportunistic scanning

Lynis scanning is opportunistic: it uses what it can find.
For example if it sees you are running Apache, it will perform an initial round of Apache related tests. When during the Apache scan it also discovers a SSL/TLS configuration, it will perform additional auditing steps on that. While doing that, it then will collect discovered certificates, so they can be scanned later as well.

In-depth security scans

By performing opportunistic scanning, the tool can run with almost no dependencies. The more it finds, the deeper the audit will be. In other words, Lynis will always perform scans which are customized to your system. No audit will be the same!

Use cases

Since Lynis is flexible, it is used for several different purposes. Typical use cases for Lynis include:
  • Security auditing
  • Compliance testing (e.g. PCI, HIPAA, SOx)
  • Vulnerability detection and scanning
  • System hardening

Resources used for testing

Many other tools use the same data files for performing tests. Since Lynis is not limited to a few common Linux distributions, it uses tests from standards and many custom ones not found in any other tool.
  • Best practices
  • CIS
  • NIST
  • NSA
  • OpenSCAP data
  • Vendor guides and recommendations (e.g. Debian Gentoo, Red Hat)

Lynis Plugins

lugins enable the tool to perform additional tests. They can be seen as an extension (or add-on) to Lynis, enhancing its functionality. One example is the compliance checking plugin, which performs specific tests only applicable to some standard.

Upgrade note
Customized profiles that included sysctl settings need to be altered. See default.prf for the correct format of the lines.

OpenStack detection
Option to disable automatic refresh of software repository
Japanese translation added, contributed by Yukio Takahara
Some tests did not show a warning text
Typo in man page for tests-from-group
New --bin-dirs to define binary directories to scan
New option --root-dir to specify a different file system to scan
Rewrite of nginx configuration parsing
Support for PHP 5.6
Redis test to detect configuration files
Test Redis configuration for several best practices
Perform permission check on Redis configuration files

Experimental features (in development)
--bin-dirs - set what directories should be scanned for binaries
--root-dir - define the root of the file system, to allow forensics

Many settings have a new alias (with dashes instead underscores)
New setting 'show-report-solution' to show solution in report

ExitFatal can now exit program with optional text
IsNotebook can detect if system is a notebook (or not)
ShowSymlinkPath and FileIsReadable test for at least one argument
StoreNginxSettings will save parsed nginx configuration

BOOT-5108 - Support for Syslinux bootloader
DBS-1882 - Redis configuration detection
DBS-1884 - Redis 'requirepass' check
DBS-1886 - Redis 'rename-command CONFIG' check
DBS-1888 - Redis 'bind localhost' check
FILE-6374 - Improved logging
KRNL-5830 - Improved logging for detected Linux kernels
KRNL-6000 - Support for multiple profiles and new format style
LOGG-2190 - Ignore MySQL files in /tmp from early MySQL 5.x releases
LOGG-2192 - New test to check opened log files that are empty

Lynis Enterprise integration
Tag 'redis-server' is added for systems running Redis

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