How to Perform a Network Security Audit in 5 Steps

How to Perform a Network Security Audit in 5 Steps

Because a security audit requires a great deal of work, the best audit managers split it into the key processes that each stage needs to cover.

1. Define Scope

The scope is one of the most important components of an audit. It defines precisely which parts of the organization’s networks and security processes will be assessed.

The scope should align with two clear aspects:

• • The available budget (either time or fiscal)

• The organization’s industry regulations

This establishes the audit standards that the following four steps will follow.

Industry regulations are an extremely useful resource, since they often identify the specific resources that an acceptable audit must examine, such as:

• GDPR requires a focus on how networks process personal data.
• PCI DSS emphasizes the transmission, storage, and use of payment card details.

Scope requirements may also vary depending on whether the audit is internal or external. For internal audits, there must be a greater emphasis on how the audit’s findings will be communicated and implemented.

2. Gather Documentation

With the scope accurately set, it’s time to address the specific network systems being audited. Thorough documentation is essential for a successful security audit, so no critical component is overlooked.

1. Start by listing all current security software, such as firewalls, antivirus programs, and SIEM tools.
2. Build a comprehensive inventory of hardware, routers, switches, firewalls, servers, and don’t forget to include virtualized environments.
3. Track software details like operating systems and licensing information to confirm compliance and keep security updates current.

This detailed inventory forms the foundation of your audit and significantly reduces the risk of oversight. To enhance clarity, create a visual map of your network and be sure to show:

• How devices and systems are connected
• Areas of segmentation, dependency, and sensitive data flow

This diagram speeds up troubleshooting and becomes a valuable reference point for future security planning.

3. Review Internal Policies

With all network devices and data flows discovered, the audit now shifts to a thorough review of internal security policies that govern how data is managed and transmitted across the organization.

Start with authentication practices:

• Identify how access is granted to end users and services
• Ensure role-based access controls (RBAC) are in place
• Compare actual network access with the ideal permissions defined in RBAC policies

Next, examine data management policies:

• Define how data from various sources moves across networks and databases
• Specify which types of data are encrypted in transit and at rest
• Ensure the audit scope includes all relevant data types for evaluation

Firewalls also require close attention, as they are critical to network defense.

The audit should review the firewall rule base to identify disabled, expired, or overly permissive rules and Inactive connections, outdated routes, and obsolete users or groups in VPN parameters. Also, don’t overlook opportunities to remove or disable unused elements – this improves performance and reduces risk

Finally, across all systems and components reviewed:

• Confirm that software and operating systems are fully patched
• Ensure all versions are current to avoid exploitable vulnerabilities

4. Conduct Penetration Testing

Penetration testing is a structured process that simulates real-world cyberattacks to identify and exploit security weaknesses. It helps organizations uncover vulnerabilities before malicious actors can take advantage of them.

The process typically follows four key stages:

Reconnaissance (Footprinting)

This initial phase involves gathering publicly available information about the target organization. Testers collect:

• Network details
• Domain names
• Employee data

The goal is to map out potential attack vectors and understand the surface area exposed to threats.

Scanning and Enumeration

In this phase, testers analyze the network to uncover vulnerabilities by:

• Identifying open ports and active services
• Detecting misconfigurations or outdated software

Common tools like Nmap and Nessus are used to perform this analysis.

Exploitation

Once vulnerabilities are identified, testers attempt to breach systems using real-world techniques such as:

• Injection SQL
• Password cracking
• Buffer overflow attacks

This mimics how actual attackers might penetrate network defenses.

Post-Exploitation

Testers assess the potential damage of a successful breach by:

• Escalating privileges
• Moving laterally across systems
• Attempting to access sensitive data or critical infrastructure

This stage reveals the depth of exposure and helps prioritize remediation efforts based on potential impact.

5. Review and Implement Changes

A standards-driven IT security audit ensures that sensitive data is properly identified, secured, and managed in alignment with industry regulations. The process begins with securing sensitive data:

• Identify all storage locations for critical information, such as payment card data (PCI-DSS) or personal health data (HIPAA)
• Where feasible, centralize storage to streamline protection and monitoring
• If centralization isn’t possible, enforce strict security controls across all storage environments

Log file management is also crucial for maintaining compliance. Ensure that log files are readily accessible for external audits, sometimes even without prior notice. Archiving is acceptable, but logs must remain easily retrievable and restorable

Access control forms another key pillar of post-audit implementation:

• Establish a rights management policy that limits access based on the sensitivity of the data
• Ensure only authorized personnel can access, retrieve, or modify critical information
• Record all access events to support breach investigations and enforce accountability