HnTool 0.1

A hardening tool for *nixes

What is it?

HnTool is an open source (GPLv2) hardening tool for Unix. It scans your system for vulnerabilities or problems in configuration files allowing you to get a quick overview of the security status of your system.

To use HnTool download it and run:

# ./hntool

Supported systems

HnTool was already tested and is working on:

• Arch Linux

• CentOS

• Debian

• Fedora

• Gentoo

• Ubuntu

If you are using HnTool on a system that is not listed above, please, let us know.

How to install

To install HnTool run the following command, as root:

# python setup.py install --prefix /usr/ --root /

How to use

Run HnTool with:

# ./hntool

You can also see the hntool(1) manual by typing ‘man hntool’ at the command line or see the usage help:

$ hntool -h

Understanding the output

There are 5 types of results:

• OK :

  Means that the item checked is fine and that you do not need to worry

• INFO:

  Means that you should know the item status, but probably it is fine. A port opened, for example.

• LOW:

  Means that a security problem was found, but it does not provides a high risk for your system.

• MEDIUM:

  Things are getting worse and you should start to worry about these itens.

• HIGH:

  You have an important security hole/problem on your system and you should fix it NOW or run and save your life.

How can I help?

There are several ways that you can contribute and help HnTool’s development. You can contribute with code, patchs, bugs and feature requests.

To report a bug or a feature request for HnTool, file a issue in our Google Code page: http://code.google.com/p/hntool/

If you’re reporting a bug, please give concrete examples of how and where the problem occurs.

If you’ve a patch (fixing a bug or a new HnTool module), then you can file an issue on Google Code too: http://code.google.com/p/hntool/issues/list

HnTool’s source is available on:

http://code.google.com/p/hntool/

How to create a module

This section documents the innards of HnTool and specifies how to create a new module.

The main HnTool program (hntool.py) runs a list of rules defined in __files__ and __services__.

• __files__ :

  defines the rules which process simple files and configs.

• __services__ :

  defines the rules which checks the security on services and daemons.

Once your module is finalized, remember to add it to the appropriate array (__files__ or __services__) defined in hntool/__init__.py

A sample HnTool module is like this (hntool/ssh.py):

import os

class rule:
        def short_name(self):
                return "ssh"
        def long_name(self):
                return "Checks security problems on sshd config file"
        def __init__(self, options):
                pass
        def analyze(self, options):
                check_results = {'ok': [], 'low': [], 'medium': [], 'high': [], 'info': []}
                ssh_conf_file = ['/etc/ssh/sshd_config', '/etc/sshd_config']

                for sshd_conf in ssh_conf_file:
                        if os.path.isfile(sshd_conf):
                                try:
                                        fp = open(sshd_conf,'r')
                                except IOError, (errno, strerror):
                                        check_results['info'].append('Could not open %s: %s' % (sshd_conf, strerror))
                                        continue

                                lines = [x.strip('\n') for x in fp.readlines()]

                                # Checking if SSH is using the default port
                                if 'Port 22' in lines or '#Port 22' in lines:
                                        check_results['low'].append('SSH is using the default port')
                                else:
                                        check_results['ok'].append('SSH is not using the default port')

                                # Closing the sshd_config file
                                fp.close()

                        return check_results
        def type(self):
                return "files"

Mostly, the code is self-explanatory. The following are the list of the methods that each HnTool module must have:

• short_name(self)

  Returns a string containing a short name of the module. Usually,this is the same as the basename of the module file.

• long_name(self)

  Returns a string containing a concise description of the module. This description is used when listing all the rules using hntool -l.

• analyze(self)

  Should return a list comprising in turn of five lists: ok, low, medium, high and info.

• type(self)

  “files” for a module processing simple files and configs “services” for a module processing services and daemons