Security Audit Program: How to Audit Your IT Infrastructure

Security audits are essential for identifying vulnerabilities before attackers do. Organizations that conduct regular security audits reduce breach risk by 60% and demonstrate compliance with industry regulations. This comprehensive guide shows you how to build and execute an effective security audit program.

What is a Security Audit?

Definition and Purpose

Security Audit: Systematic evaluation of an organization's security posture against established standards and best practices.

Primary Objectives:

Identify security vulnerabilities and weaknesses
Verify compliance with policies and regulations
Assess effectiveness of security controls
Provide remediation recommendations
Establish security baseline metrics
Demonstrate due diligence to stakeholders

Types of Security Audits:

Internal Audits: Conducted by internal team
External Audits: Third-party assessment
Compliance Audits: Regulatory requirements (SOC 2, ISO 27001)
Technical Audits: Infrastructure and systems
Process Audits: Policies and procedures
Penetration Tests: Simulated attacks

Security Audit Methodology

Phase 1: Planning and Scoping

Define Audit Objectives:

[ ] Identify audit purpose (compliance, risk assessment, etc.)
[ ] Determine audit scope (systems, applications, processes)
[ ] Define audit standards (NIST, ISO, CIS)
[ ] Set timeline and milestones
[ ] Assign audit team roles
[ ] Identify stakeholders

Scope Considerations:

In-Scope:
- Network infrastructure
- Servers and workstations
- Applications and databases
- Cloud services
- Security policies
- Access controls
- Data protection measures
Out-of-Scope:
- Third-party managed services (unless specified)
- Personal devices (unless BYOD policy audit)
- Legacy systems scheduled for decommission

Resource Requirements:

Audit team (2-5 people depending on scope)
Audit tools and software
Documentation access
System access credentials
Stakeholder time for interviews
Budget for external assessments

Phase 2: Information Gathering

Documentation Review:

[ ] Security policies and procedures
[ ] Network diagrams
[ ] System inventories
[ ] Access control lists
[ ] Previous audit reports
[ ] Incident response records
[ ] Change management logs
[ ] Vendor contracts and SLAs

Stakeholder Interviews:

IT management
Security team
System administrators
Application owners
Compliance officers
End users (sample)

Interview Questions:

How are security policies communicated?
What is the change management process?
How are incidents detected and responded to?
What security training is provided?
How often are access rights reviewed?

Phase 3: Technical Assessment

Network Security Audit:

Infrastructure Review:

[ ] Firewall configurations
[ ] Router and switch security
[ ] Network segmentation
[ ] VPN configurations
[ ] Wireless network security
[ ] DMZ implementation
[ ] Network monitoring tools

Testing Activities:

Port scanning (Nmap)
Vulnerability scanning (Nessus, Qualys)
Network traffic analysis
Firewall rule review
Configuration audits

System Security Audit:

Server Hardening:

[ ] Operating system patches
[ ] Unnecessary services disabled
[ ] Strong authentication configured
[ ] Audit logging enabled
[ ] Encryption settings
[ ] Backup configurations
[ ] Antivirus/EDR deployment

Workstation Security:

[ ] Endpoint protection
[ ] Patch management
[ ] Local admin restrictions
[ ] Disk encryption
[ ] Screen lock policies
[ ] USB port controls

Application Security Audit:

Web Applications:

[ ] OWASP Top 10 vulnerabilities
[ ] Authentication mechanisms
[ ] Session management
[ ] Input validation
[ ] Error handling
[ ] Security headers
[ ] API security

Testing Methods:

Automated scanning (Burp Suite, OWASP ZAP)
Manual testing
Code review (if access available)
Configuration review
Dependency analysis

Database Security:

[ ] Access controls
[ ] Encryption at rest
[ ] Encryption in transit
[ ] Audit logging
[ ] Backup security
[ ] Privilege separation
[ ] SQL injection protection

Get Complete Security Audit Checklist →

Phase 4: Access Control Review

User Access Audit:

Identity Management:

[ ] User provisioning process
[ ] Account creation procedures
[ ] Naming conventions
[ ] Default account management
[ ] Service account controls

Access Rights Review:

[ ] Principle of least privilege
[ ] Segregation of duties
[ ] Privileged account management
[ ] Dormant account identification
[ ] Terminated employee access removal

Authentication Assessment:

[ ] Password policies (complexity, age, history)
[ ] Multi-factor authentication deployment
[ ] Single sign-on implementation
[ ] Biometric authentication
[ ] Certificate-based authentication

Testing Activities:

Access rights sampling
Privilege escalation testing
Orphaned account identification
Shared account usage review
Password policy compliance check

Phase 5: Data Protection Audit

Data Classification:

[ ] Data classification scheme exists
[ ] Data owners identified
[ ] Classification labels applied
[ ] Handling procedures defined
[ ] Storage requirements met

Encryption Assessment:

[ ] Data at rest encryption
[ ] Data in transit encryption
[ ] Key management practices
[ ] Certificate management
[ ] Encryption algorithm strength

Data Loss Prevention:

[ ] DLP tools deployed
[ ] Data exfiltration controls
[ ] Email security
[ ] Cloud storage controls
[ ] Removable media policies
[ ] Print controls

Privacy Compliance:

[ ] GDPR compliance (if applicable)
[ ] CCPA compliance (if applicable)
[ ] HIPAA compliance (if applicable)
[ ] Data retention policies
[ ] Data disposal procedures
[ ] Privacy notices

Phase 6: Policy and Procedure Review

Policy Assessment:

Required Policies:

[ ] Information security policy
[ ] Acceptable use policy
[ ] Access control policy
[ ] Password policy
[ ] Remote access policy
[ ] Incident response policy
[ ] Business continuity policy
[ ] Data classification policy
[ ] Change management policy

Policy Evaluation Criteria:

Comprehensive coverage
Clear and understandable
Aligned with regulations
Regularly reviewed and updated
Management approved
Communicated to employees
Compliance monitored

Procedure Review:

[ ] Incident response procedures
[ ] Change management procedures
[ ] Access provisioning procedures
[ ] Backup and recovery procedures
[ ] Patch management procedures
[ ] Vendor management procedures

Phase 7: Physical Security Audit

Facility Security:

[ ] Perimeter security
[ ] Access control systems
[ ] Visitor management
[ ] Surveillance cameras
[ ] Security guards
[ ] Alarm systems

Data Center Security:

[ ] Access restrictions
[ ] Environmental controls
[ ] Fire suppression
[ ] Power backup (UPS, generators)
[ ] Cable security
[ ] Equipment destruction procedures

Office Security:

[ ] Workstation security
[ ] Clean desk policy
[ ] Printer/copier security
[ ] Document destruction
[ ] Secure storage
[ ] After-hours security

Audit Tools and Techniques

Vulnerability Scanning Tools

Network Scanners:

Nmap: Port scanning and service detection
Nessus: Comprehensive vulnerability scanning
Qualys: Cloud-based vulnerability management
OpenVAS: Open-source vulnerability scanner
Rapid7 InsightVM: Vulnerability risk management

Web Application Scanners:

Burp Suite: Web security testing
OWASP ZAP: Open-source web scanner
Acunetix: Automated web vulnerability scanner
Nikto: Web server scanner

Configuration Assessment:

Lynis: Unix/Linux security auditing
CIS-CAT: CIS Benchmark assessment
Microsoft SCCM: Windows configuration management
Ansible: Configuration automation and audit

Penetration Testing Tools

Exploitation Frameworks:

Metasploit
Cobalt Strike
Core Impact

Password Cracking:

John the Ripper
Hashcat
Hydra

Network Analysis:

Wireshark
tcpdump
NetworkMiner

Compliance Scanning

Compliance Tools:

Qualys Policy Compliance
Tenable SecurityCenter
Rapid7 InsightVM
Chef InSpec

Frameworks Supported:

PCI DSS
HIPAA
SOC 2
ISO 27001
NIST CSF
CIS Controls

Audit Findings and Reporting

Risk Classification

Severity Levels:

Critical:

Immediate exploitation possible
Significant business impact
Regulatory compliance violation
Public-facing vulnerabilities
Remediation: Immediate (24-48 hours)

High:

High probability of exploitation
Moderate to high business impact
Multiple vulnerabilities combined
Remediation: 1-2 weeks

Medium:

Moderate exploitation difficulty
Limited business impact
Best practice deviations
Remediation: 30-60 days

Low:

Difficult to exploit
Minimal business impact
Informational findings
Remediation: 90+ days

Audit Report Structure

Executive Summary:

Audit objectives and scope
Overall security posture assessment
Critical findings summary
High-level recommendations
Compliance status

Detailed Findings: For each finding:

Title and severity
Description
Risk and business impact
Evidence (screenshots, logs)
Affected systems
Remediation recommendations
Remediation timeline

Technical Appendices:

Vulnerability scan results
Configuration issues
Testing methodology
Tools used
Scope details

Sample Finding Format

Finding: Unpatched Critical Vulnerabilities
Severity: Critical
Category: Patch Management

Description:
Multiple servers are running outdated software with known critical 
vulnerabilities (CVE-2024-XXXX, CVE-2024-YYYY).

Risk:
Attackers can exploit these vulnerabilities to gain unauthorized access,
execute arbitrary code, or cause denial of service.

Affected Systems:
- Web Server 1 (10.0.1.15)
- Database Server 3 (10.0.2.20)
- Application Server 5 (10.0.3.25)

Recommendation:
1. Implement emergency patching within 48 hours
2. Establish monthly patch management cycle
3. Deploy patch management tool (WSUS, SCCM)
4. Create patch testing procedures

Priority: Immediate action required

Creating an Audit Program

Audit Schedule

Annual Audit Calendar:

Quarterly:

Access rights review
Policy compliance check
Vulnerability scanning
Patch compliance audit

Semi-Annual:

Network security audit
Application security review
Physical security inspection

Annual:

Comprehensive security audit
Third-party penetration test
Business continuity testing
Compliance certification audit

Continuous Monitoring

Automated Monitoring:

Security Information and Event Management (SIEM)
Intrusion Detection/Prevention Systems (IDS/IPS)
File Integrity Monitoring (FIM)
Log aggregation and analysis
Vulnerability scanning (weekly/monthly)
Configuration compliance monitoring

Key Metrics:

Number of vulnerabilities by severity
Patch compliance rate
Time to remediate vulnerabilities
Number of security incidents
Policy compliance rate
Access review completion rate

Audit Team Structure

Internal Audit Team:

IT Audit Manager: Overall program oversight
Security Auditor: Technical assessments
Compliance Specialist: Regulatory requirements
Systems Auditor: Infrastructure review

External Resources:

Third-party penetration testers
Compliance auditors
Specialized security consultants
Industry experts

Remediation Tracking

Remediation Plan

Components:

Finding ID and description
Assigned owner
Remediation steps
Target completion date
Status tracking
Verification method
Closure criteria

Tracking Methods:

Ticketing system (Jira, ServiceNow)
Remediation tracker spreadsheet
GRC platform
Regular status meetings

Verification and Closure

Verification Activities:

Re-scan vulnerable systems
Review configuration changes
Test controls
Interview stakeholders
Review documentation

Closure Criteria:

Remediation fully implemented
Testing confirms resolution
Documentation updated
Risk accepted by management (if applicable)
Auditor verification complete

Compliance Audit Requirements

SOC 2 Audit

Trust Service Criteria:

Security
Availability
Processing integrity
Confidentiality
Privacy

Audit Activities:

Control testing
Evidence collection
Process observation
Documentation review
Management interviews

ISO 27001 Audit

Audit Stages:

Stage 1: Documentation review
Stage 2: Implementation audit
Surveillance audits (annual)
Recertification (3 years)

Key Areas:

ISMS scope and boundaries
Risk assessment and treatment
Control implementation
Management review
Continuous improvement

PCI DSS Audit

12 Requirements:

Firewall configuration
Password management
Cardholder data protection
Encryption in transit
Antivirus deployment
Secure systems and applications
Access control
Unique IDs
Physical access restrictions
Network monitoring
Regular testing
Information security policy

Best Practices

Before the Audit

Preparation:

[ ] Conduct pre-audit assessment
[ ] Remediate known issues
[ ] Organize documentation
[ ] Brief stakeholders
[ ] Prepare system access
[ ] Review previous findings

During the Audit

Cooperation:

Respond promptly to requests
Provide accurate information
Maintain communication
Document interactions
Address concerns immediately
Avoid defensive posture

After the Audit

Follow-up:

Review findings promptly
Prioritize remediation
Track progress
Update documentation
Communicate status
Plan for re-audit

Free Security Audit Resources

Comprehensive Audit Package

Our security audit toolkit includes:

Complete security audit checklist
Risk assessment templates
Finding report templates
Remediation tracking spreadsheet
Interview question guides
Policy review checklists
Compliance mapping guides

Download Free Security Audit Toolkit →

Security Templates:

Conclusion

Regular security audits are essential for maintaining a strong security posture and demonstrating compliance. By following a structured audit methodology and implementing continuous monitoring, organizations can identify and remediate vulnerabilities before they're exploited.

Implementation Checklist:

[ ] Define audit scope and objectives
[ ] Download audit checklist template
[ ] Assemble audit team
[ ] Gather documentation
[ ] Conduct technical assessments
[ ] Review access controls
[ ] Audit policies and procedures
[ ] Document findings
[ ] Create remediation plan
[ ] Track progress to closure
[ ] Schedule next audit

Quick Start Guide:

Start with vulnerability scanning
Review critical systems first
Focus on high-risk areas
Document everything
Prioritize remediation
Build audit program incrementally

Next Steps:

Don't wait for a breach to identify vulnerabilities. Download our comprehensive security audit toolkit and start assessing your security posture today.