8 Linux Aide Best Practices

Aide is a free and open source intrusion detection system (IDS). It creates a database of files and directories, called a baseline, and can then be used to monitor the system for changes. Aide can be used to detect unauthorized changes to files, as well as changes to permissions, ownership, and other file attributes.

In this article, we will discuss eight best practices for using Aide. We will cover topics such as creating a baseline, scheduling scans, and configuring email alerts. By following these best practices, you can use Aide to effectively monitor your Linux system for changes.

1. Use aide –init to create a database.

When you create a database with aide –init, it creates a snapshot of your system at that moment in time. You can then use this database as a reference point to check for changes later on.

If you don’t use aide –init to create a database, then you have no way of knowing what has changed on your system over time. This makes it difficult to spot potential security issues, because you won’t be able to tell if a change is normal or not.

Aide –init is a simple command, and it only takes a few seconds to run. There’s no excuse not to use it, so make sure you always create a database before starting any other work with Linux Aide.

2. Run aide –check daily (or more often).

The main purpose of Aide is to create a database of file hashes, so that it can detect changes to files. However, the database itself is stored as a file, and so it is susceptible to changes. If an attacker were to gain access to your system and modify the Aide database, they could potentially make changes to files without being detected.

By running aide –check on a regular basis, you can be sure that the Aide database has not been tampered with, and that it is still accurate.

3. Review the output of aide –check regularly.

The output of aide –check contains a wealth of information about the current state of your system’s files, and it can be easy to miss something important if you’re not paying close attention. By reviewing the output regularly, you can ensure that you don’t miss any changes that could potentially be malicious.

Additionally, review the output of aide –check after making any changes to your system’s configuration. This will help you to verify that the changes you made were applied correctly, and it will also allow you to see how the changes have affected your system’s overall security posture.

4. Keep your AIDE configuration file in version control.

If you make changes to your AIDE configuration file and something goes wrong, it can be difficult to track down the problem and revert back to a working configuration. However, if you have your configuration file in version control, you can simply checkout an earlier version to get things working again.

Additionally, having your AIDE configuration file in version control gives you a history of changes that can be useful for auditing purposes. If you ever need to go back and see what changed and when, you can simply look at the commit history.

5. Don’t use AIDE as your only security measure.

AIDE is a great tool for detecting changes to files, but it’s not perfect. There are many ways for an attacker to bypass AIDE, and if you’re relying on AIDE alone to keep your system secure, you’re setting yourself up for disappointment.

Instead, use AIDE as one part of a comprehensive security strategy that includes other measures such as intrusion detection/prevention systems, firewalls, and proper file permissions.

6. Make sure you know how to restore from backups.

If you ever find yourself in the situation where you need to restore your system from a backup, the last thing you want to do is realize that you don’t know how. That’s why it’s important to make sure that you understand how to use the tool before you actually need to use it.

Fortunately, Linux Aide is relatively simple to use and there are plenty of resources available online that can help you learn how to use it. Just make sure that you take the time to learn how to use it before you actually need it.

7. Be aware of false positives and negatives.

False positives are when Aide reports a change when there actually hasn’t been one. This can happen for a number of reasons, but the most common is that the file in question has changed permissions or ownership.

False negatives are when Aide doesn’t report a change when there actually has been one. This is usually due to human error, such as forgetting to add a new file to the configuration.

Both false positives and false negatives can lead to serious security issues, so it’s important to be aware of them and take steps to avoid them.

8. Consider using other tools, such as OSSEC or Tripwire.

Linux Aide is a great tool for monitoring file integrity, but it’s not the only tool out there. There are other tools available that can complement or even replace Linux Aide in your environment.

For example, OSSEC is another open source file integrity monitoring tool that can be used on Linux systems. It has many of the same features as Linux Aide, but also includes additional features such as log analysis and intrusion detection.

Tripwire is another popular file integrity monitoring tool that can be used on Linux systems. It’s similar to Linux Aide in that it can monitor files for changes, but it also includes additional features such as policy management and reporting.

While Linux Aide is a great tool, it’s important to consider using other tools as well to get the most comprehensive file integrity monitoring possible.