Hardening AIX

The basic principles behind a more secure UNIX system

Hardening AIX is not about a single setting or a magic command. It is a holistic approach where the aim is to reduce the attack surface, strengthen access controls and ensure that the system behaves in a predictable and verifiable manner. IBM’s guidelines for AIX 7.3 describe a number of core principles that all organizations should have in place – regardless of whether the environment is small or consists of hundreds of servers.

Here is a summary of the most important concepts and principles.

Read more in IBM’s official guide for AIX 7.3 Security Hardening

AIX 7.3 Security Hardening

Would you like to delve into the details? IBM’s own documentation goes through all the security features in AIX 7.3 – from policies and profiles to RBAC, network security and system integrity. Perfect for those who want to work in a structured way with hardening.

Reduce the attack surface

The less the system exposes, the harder it becomes to attack.

Key principles:

  • Uninstall or disable services you do not use.

  • Close ports and protocols that are not needed.

  • Restrict access to remote administration and logins.

This is often the most effective and at the same time simplest form of hardening.

Strengthen authentication and access control

AIX offers advanced mechanisms to control who can do what.

Important measures:

  • Activate and configure RBAC (Role-Based Access Control).

  • Implement minimal privileges – users should only have exactly what they need.

  • Use secure password policies and lockout rules.

  • Log and monitor all changes in permissions.

RBAC is particularly powerful for avoiding overuse of root.

Protect system files and file permissions

A large part of AIX security is about ensuring that files cannot be manipulated.

Basic steps:

  • Use trusted computing base (TCB) to verify the integrity of the system.

  • Run regular checks with tcbck.

  • Secure directories such as /etc, /usr and sensitive binaries.

TCB is a unique and strong mechanism that distinguishes AIX from many other UNIX variants.

Strengthen the security of the network stack

AIX has in-depth features for controlling network behavior.

Focus on:

  • Configure TCP/IP-security tunables.

  • Restrict ICMP, routing functions and unnecessary network services.

  • Ensure correct use of SSH with modern encryption algorithms.

This reduces the risks of network-related intrusions.

Patching and revision are part of hardening

A hardened system that is not maintained stops being hardened.

Guidelines:

  • Keep AIX Technology Levels and Service Packs updated.

  • Use oslevel and instfix to check the version status.

  • Implement recurring security audits and checks.

Monitoring and logging – the heart of security work

Detecting problems quickly is as important as preventing them.

AIX offers:

  • Audit subsystem (AIX Audit).

  • System logging (syslogd / rsyslog).

  • FIM (File Integrity Monitoring) through TCB.

A good hardening strategy always includes correct and centralized log management.

Hardening AIX is about discipline, consistency and following proven principles. By eliminating unnecessary services, strengthening access controls, protecting system files and actively maintaining the environment, you create a robust, hard-to-breach platform that resists both external and internal threats.

Why LOAD

As an IBM Platinum Partner, LOAD helps Swedish companies implement solutions that match their needs for performance, security, and easy operation.
We offer consulting, design, implementation, and proactive support – so you can focus on business instead of infrastructure.

Why LOAD

As an IBM Platinum Partner, LOAD helps Swedish companies implement solutions that match their needs for performance, security, and easy operation.
We offer consulting, design, implementation, and proactive support – so you can focus on business instead of infrastructure.