Auditing Compliance | Security

Introduction

Auditing and Compliance are critical aspects of maintaining a secure and reliable Linux environment. Auditing involves tracking and recording system activities to ensure accountability, while compliance ensures that the system adheres to regulatory standards and organizational policies.

Understanding Linux Auditing

Linux auditing involves monitoring and logging system events such as user logins, file accesses, and system changes. This helps in detecting unauthorized activities and ensuring that the system is secure.

Installing the Audit Daemon

The first step in setting up auditing on a Linux system is to install the audit daemon (auditd).

Use the following command to install auditd on a Debian-based system:

sudo apt-get install auditd

On a Red Hat-based system, use the following command:

sudo yum install audit

Configuring the Audit Daemon

After installing auditd, configure it by editing the /etc/audit/auditd.conf file. This file contains various parameters that control the behavior of the audit daemon.

# Example /etc/audit/auditd.conf
log_file = /var/log/audit/audit.log
log_format = RAW
flush = INCREMENTAL
freq = 50

Setting Audit Rules

Audit rules define what events should be logged. These rules can be configured in the /etc/audit/audit.rules file or dynamically added using the auditctl command.

To log all changes to the /etc/passwd file, add the following rule:

auditctl -w /etc/passwd -p wa -k passwd_changes

This rule specifies that writes (w) and attribute changes (a) to the /etc/passwd file should be logged with the key passwd_changes.

Viewing Audit Logs

Audit logs are typically stored in the /var/log/audit/audit.log file. You can use the ausearch and aureport commands to search and generate reports from the audit logs.

To search for all events related to the passwd_changes key, use:

ausearch -k passwd_changes

Compliance in Linux

Compliance involves ensuring that the Linux system adheres to various regulatory standards and organizational policies. This can include data protection regulations, security standards, and internal policies.

Common Compliance Standards

Some common compliance standards that may apply to Linux systems include:

General Data Protection Regulation (GDPR)
Payment Card Industry Data Security Standard (PCI DSS)
Health Insurance Portability and Accountability Act (HIPAA)
Federal Information Security Management Act (FISMA)

Tools for Compliance

Several tools can help ensure compliance on Linux systems. These include:

OpenSCAP: An open-source project providing tools for implementing and verifying security policies.
Lynis: A security auditing tool for Unix-based systems that helps in compliance checking.
Auditd: As discussed, it helps in tracking and logging system events which can be crucial for compliance.

Example: Using OpenSCAP

OpenSCAP can be used to scan a system for compliance with security policies. First, install OpenSCAP:

sudo apt-get install libopenscap8

Then, use the following command to perform a scan:

oscap xccdf eval --profile xccdf_org.ssgproject.content_profile_pci-dss /usr/share/xml/scap/ssg/content/ssg-debian8-ds.xml

Conclusion

Auditing and compliance are essential components of maintaining a secure and trustworthy Linux environment. By using tools like auditd and OpenSCAP, administrators can ensure that their systems are both secure and compliant with various standards and regulations.

Auditing and Compliance in Linux