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auditd

Table of Contents

  1. Module Description
  2. Usage - Configuration options and additional functionality
  3. Audispd
  4. Reference
  5. Limitations
  6. Copyright

Module Description

This module installs, and configures the auditd service and ruleset. The currently supported platforms are:

  • RHEL 6/7
  • CentOS 6/7
  • Ubuntu 16.04

By default, the only rules that are applied are the buffer size, and action to take on failure.

Usage

Installing and starting

include ::auditd

Specifying Rules

Rules can be specified via four parameters:

  1. auditd::base_rules
  2. auditd::main_rules
  3. auditd::server_rules
  4. auditd::finalize_rules

Each location takes a yaml list of rules like so:

auditd::main_rules:
  - '-a always,exit -F path=/etc/passwd -F perm=wa -F key=accounts'
  - '-a always,exit -F path=/etc/gshadow -F perm=wa -F key=accounts'

The purpose of each location is as follows:

  • auditd::base_rules is loaded before any other rules are processed
  • auditd::main_rules is the primary set of rules to use
  • auditd::server_rules are any rules specific to a given node, that should load after the primary rules
  • auditd::finalize_rules are any rules that should load after all other rules. The common use for this is to lock the rules from changing without a reboot.

Note about augenrules

Currently, this module depends on the auditctl and augenrules binaries to load rules. While there is a parameter to not use augenrules, there currently isn't any alternative that is tried.

Note about service restarts

Due to some implementations of auditd not being able to be fully restarted, configuration changes for the service its self trigger a service reload. Because Puppet doesn't provide an easy way to trigger service reloads instead of restarts, this is handled by a case statement and exec. Currently, the following service providers should work when sepecified:

  • redhat
  • systemd

Additional service providers may be added in the future.

Audispd

This module also allows for some basic audispd (audit event multiplexor) configuration.

Usage

By default, this module will attempt to manage a file at /etc/audisp/audispd.conf, and install additional audispd plugins. You can prevent management of audispd by setting the auditd::audisp::manage parameter to false.

Plugins

auditd::audisp::plugin is a resource type which can be used to create plugin configuration files. If the auditd::audisp::plugins parameter is not empty, this module will attempt to create a configuration file for the plugin(s) specified in the parameter.

Reference

Classes

Public Classes

  • auditd: Main class, includes all other classes.
  • auditd::audisp::plugins: Class to set up specified audispd plugins.

Private Classes

  • auditd::install: Handles package installation.
  • auditd::config: Handles auditd configuration.
  • auditd::rules: Handles auditd rules.
  • auditd::service: Handles auditd service and rule loading.
  • auditd::audisp: Handles management of audispd
  • auditd::audisp::install: Handles installation of audispd plugins
  • auditd::audisp::config: Handles configuration of audispd

Types

auditd::audisp::plugin

This type creates a configuration file for a audispd plugin. It accepts the following parameters:

  • 'active' - Whether or not the plugin should be activated. Valid options: Boolean. Default value: true
  • 'direction' - Which direction events flow to the plugin. Valid options: 'in' or 'out'. Default value: 'out'
  • 'path' - The absolute path to the plugin executable. Valid options: String . Default value: undef
  • 'type' - How the plugin wants to run. Valid options: 'builtin' or 'always'. Default value: 'always'
  • 'args' - Maximum of 2 arguments to pass to the child program. Valid options: Array containing strings. Default value: []
  • 'format' - The format to send events as. Valid options: 'binary' or 'string'. Default value: 'string'

It uses the title of the resource to create a file called "${title}.conf", under the directory specified in auditd::audisp::plugindir.

Parameters

The below parameters are available in the ::auditd class. The man page for auditd.conf can be referenced for more detailed description of each option.

auditd::conf

The fullpath of the main auditd configuration file. Valid options: string containing fullpath. Default value: '/etc/audit/auditd.conf'

auditd::log_file

The file to use for audit logging. Valid options: string containing fullpath. Default value: '/var/log/audit/audit.log'

auditd::log_format

The log format describes how the information should be stored on disk. Valid options: string containing log format. Default value: 'RAW'

auditd::log_group

The group that is applied to the log file's permissions. Valid options: string containing group. Default value: 'root'

auditd::priority_boost

Tells the audit daemon how much of a priority boost it should take. Valid options: 0 or positive integer. Default value: 4

auditd::flush

Tells the audit daemon how to handle flushing audit records to disk. Valid options: string containing flush method. Default value: 'INCREMENTAL'

auditd::freq

Configures how often an explicit flush to disk is issued. Valid options: positive ingeger. Default value: 20

auditd::num_logs

The number of log files to keep if rotate is given as the max_log_file_action. Valid options: integer between 0 and 99. Default value: 5

auditd::disp_qos

Controls whether you want blocking/lossless or non-blocking/lossy communication between the audit daemon and the dispatcher. Valid options: string containing communication type. Default value: 'lossy'

auditd::dispatcher

Application that all events are passed to. Valid options: string containing the path to a program. Default value: '/sbin/audispd'

auditd::name_format

How node names are inserted into event stream. Valid options: string containing the node name format. Default value: 'NONE'

auditd::admin_name

Machine name if auditd::name_format is set to user. Valid options: string containing the machine name. Default value: undef

auditd::max_log_file

Maximum log file size in MB. Valid options: positive numeric. Default value: 6

auditd::max_log_file_action

Action to take when auditd::max_log_file size is reached. Valid options: string containing action to take. Default value: 'ROTATE'

auditd::space_left

When the machine reaches auditd::space_left diskspace (in MB) remaining, take an action. Valid options: positive numeric. Default value: 75

auditd::space_left_action

Action to take when the auditd daemon detects low disk space. Valid options: string containing the action to take. Default value: 'SYSLOG'

auditd::action_mail_acct

Email alert is sent to when auditd::space_left_action is set to 'email'. Valid options: string containing email. Default value: 'root'

auditd::admin_space_left

'Last chance' threshold in MB to take action when machine is low on disk space. Valid options: positive numeric. Default value: 50

auditd::admin_space_left_action

See auditd::space_left_action.

auditd::disk_full_action

Action to take when partition used for logs is full. Valid options: string containing action. Default value: 'SUSPEND'

auditd::disk_error_action

Action to take when disk error is occured when writing or rotating logs. Valid options: string containing action. Default value: 'SUSPEND'

auditd::tcp_listen_port

TCP port to listen for events from other machines on. Valid options: integer between 1 and 65535. Default value: undef

auditd::tcp_listen_queue

How many pending connections to allow. Valid options: positive integer. Default value: 5

auditd::tcp_max_per_addr

How many connections per-host are allowed. Valid options: integer between 1 and 1024. Default value: 1

auditd::use_libwrap

Whether or not to use tcp_wrappers to restrict connections. Valid options: boolean. Default value: true

auditd::tcp_client_ports

Specifies which incoming ports are allowed for client connections. Valid options: integer between 1 and 65535, or two integers seperated with a '-'. Default value: undef

auditd::tcp_client_max_idle

Number of seconds a client is allowed to remain idle. Valid options: positive integer. Default value: 0

auditd::enable_krb5

If enabled, Kerberos 5 will be used for authentication. Valid options: boolean. Default value: false

auditd::krb5_principal

The principal for the server. Valid options: string containing the principal. Default value: 'auditd'

auditd::krb5_key_file

The key for the server's principal. Valid options: string containing path to key. Default value: undef

auditd::service_manage

Whether to manage the service with this module. Valid options: boolean. Default value: true

auditd::service_enable

Whether to enable the the service on system start. Valid options: boolean. Default value: true

auditd::service_name

The name of the auditd serivce. Valid options: string containing the service name. Default value: 'auditd'

auditd::service_provider

The service provider that would normally be used with the service type. Valid options: string containing the service provider. Default value: 'systemd'

Note that this is normally determined automatically by Puppet. Due to how service reloads are managed, we have to manually specify it to trigger a service reload instead of a restart.

auditd::manage_package

Whether to manage the package with this module. Valid options: boolean. Default value: true

auditd::package_name

Name of the auditd package. Valid options: string containing package name. Default value: 'audit'

auditd::package_state

State to use for package type. Valid options: string containing package state. Default value: 'present'

auditd::use_augenrules

Whether to use augenrules format for rule creation (i.g. 'rules.d' format; not monolithic file). Valid options: boolean. Default value: true

Note, that currently if set to false, then no rules will be applied or loaded by the module.

auditd::rulesd_dir

Directory to use for 'rules.d' format. Valid options: string containing path to directory. Default value: '/etc/audit/rules.d'

auditd::purge_rules

Whether to remove any files Puppet doesn't manage from the directory specified by auditd::rulesd_dir. Valid options: boolean. Default value: true

auditd::rules_buffer_size

auditd::rules_failure_mode

auditd::base_rules

Rules to load before any other, after the buffer and failure options. Valid options: list containing strings of rules. Default value: undef

auditd::main_rules

Rules to be loaded as the 'core' set. Valid options: list containing strings of rules. Default value: undef

auditd::server_rules

Rules to be loaded after the main rules, to be used for node-specific configuration. Valid options: list containing strings of rules. Default value: undef

auditd::finalize_rules

Rules to be loaded after any other rule specified. Mainly used if you wanted to lock rules from changing without a reboot. Valid options: list containing strings of rules. Default value: undef

auditd::audisp::manage

Whether to manage audispd with this module or not. Valid options: Boolean. Default value: true

auditd::audisp::audispd_conf

The configuration file to use for audispd. Vaild options: String. Default value: '/etc/audisp/audispd.conf'

auditd::audisp::plugindir

The path to the 'plugins.d' directory for audispd. Valid options: String. Default value: '/etc/audisp/plugins.d'

auditd::audisp::q_depth

How large the internal queue should be for audispd. Valid options: Numeric. Default value: 80

auditd::audisp::overflow_action

How audispd should react when its internal queue overflows. Valid options: String. Default value: 'syslog'

auditd::audisp::audispd_priority_boost

How much of a priority boost audispd should have. Valid options: Postitive Integer. Default value: 4

auditd::audisp::max_restarts

How many attempts audispd will make to restart crashed plugins. Valid options: Positive Integer. Default value: 10

auditd::audisp::audispd_name_format

How node names are inserted into event stream. Valid options: String. Default value: hostname

auditd::audisp::audispd_name

String identifying the machine when using the 'user' name_format. Valid options: String. Default value: undef

auditd::audisp::install_plugins

Whether to install additional audispd plugins. Valid options: Boolean. Default value: true

auditd::audisp::plugin_package_name

The name of the package containing the audispd plugins. Valid options: String. Default value: 'audispd-plugins'

auditd::audisp::plugins

A list of plugins to configure on a server. Vaild options: Hash of plugins and parameters. Default value: undef

Limitations

Currently the module is only really useful on systems that have augenrules and use the rules.d directory. While the option is there to disable augenrules, there currently isn't any alternative method implemented.

Copyright

   Copyright 2016 Nexcess.net

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.