In 2008, the U.S. defense industry experienced one of the largest cyber intrusions in its history. That breach sparked a collaborative effort to define a prioritized, actionable cybersecurity framework. That effort eventually evolved into the CIS Critical Security Controls, now maintained by the Center for Internet Security (CIS).
Today, the CIS Critical Security Controls (formerly known as the CIS Top 20) provide organizations with a proven roadmap for defending against the most common and damaging cyber threats.
In this guide, we’ll break down all 20 CIS Critical Security Controls, explain why they matter, and outline how organizations can implement them effectively.
What Are the CIS Critical Security Controls?
The CIS Critical Security Controls (CIS Controls) are a prioritized set of cybersecurity best practices designed to:
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Prevent common cyberattacks
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Detect malicious activity quickly
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Respond and recover efficiently
Originally introduced as the “CIS Top 20,” the framework has evolved, but the concept of 20 foundational controls remains widely referenced.
The controls are practical, prescriptive, and aligned with other major standards like NIST and ISO frameworks.
Understanding CIS Implementation Groups (IG1, IG2, IG3)
Before diving into the 20 CIS Critical Security Controls, it’s important to understand Implementation Groups (IGs).
CIS recognizes that not all organizations have the same cybersecurity maturity or resources. To address this, the framework divides implementation into three tiers:
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IG1 – Basic Cyber Hygiene
For small organizations with limited IT and cybersecurity resources. -
IG2 – Intermediate Security
For organizations with moderate risk exposure and compliance requirements. -
IG3 – Advanced Security
For enterprises handling highly sensitive data or critical infrastructure.
Each control includes sub-controls mapped to these groups. An IG3 organization is expected to implement all safeguards, while IG1 focuses on foundational protections.
Basic CIS Critical Security Controls (1–6)
The first six CIS Critical Security Controls focus on fundamental cyber hygiene. These are continuous, ongoing practices that form the backbone of a secure environment.
1. Inventory and Control of Hardware Assets
What It Is:
Actively managing and maintaining an accurate inventory of all authorized devices connected to your network.
Why It Matters:
You cannot secure what you cannot see. Unauthorized devices — including BYOD systems — introduce significant risk.
Examples of Tools:
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Asset discovery tools
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Network scanning protocols (ICMP, TCP SYN/ACK)
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Automated device inventory platforms
2. Inventory and Control of Software Assets
What It Is:
Tracking and managing all authorized software to prevent installation or execution of unauthorized applications.
Why It Matters:
Attackers frequently exploit unpatched or shadow IT software.
Examples of Tools:
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SIEM platforms
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Application whitelisting tools
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Intrusion Detection Systems (IDS)
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Endpoint protection solutions
3. Continuous Vulnerability Management
What It Is:
Ongoing identification and remediation of system vulnerabilities.
Why It Matters:
Threat intelligence evolves daily. Without continuous monitoring, organizations remain exposed.
Examples of Tools:
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Vulnerability scanners
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SIEM solutions
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Incident Response Plans (IRP)
4. Controlled Use of Administrative Privileges
What It Is:
Restricting and monitoring admin-level access.
Why It Matters:
Compromised admin credentials can lead to total system takeover.
Examples of Tools:
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Privileged Access Management (PAM) solutions
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Admin activity logging systems
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MFA for privileged accounts
5. Secure Configuration for Hardware and Software
What It Is:
Establishing secure baseline configurations for devices and systems.
Why It Matters:
Default settings are often insecure and easily exploited.
Examples of Tools:
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Standardized configuration policies
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Security Content Automation Protocol (SCAP)
6. Maintenance, Monitoring, and Analysis of Audit Logs
What It Is:
Collecting and analyzing logs to detect suspicious activity.
Why It Matters:
Without logs, breaches may go undetected for months.
Examples of Tools:
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SIEM platforms
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Firewall logging
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Endpoint logging systems
Foundational CIS Critical Security Controls (7–15)
Controls 7–15 introduce more technical safeguards that strengthen infrastructure protection.
7. Email and Web Browser Protections
Protect users from phishing and malicious web activity.
8. Malware Defense
Deploy layered endpoint and network malware protection.
9. Limitation and Control of Network Ports, Protocols, and Services
Actively manage open ports and exposed services.
10. Data Recovery Capability
Maintain tested backup and restoration procedures.
11. Secure Configuration for Network Devices
Harden firewalls, routers, and switches.
12. Boundary Defense
Monitor and defend network perimeters.
13. Data Protection
Classify and encrypt sensitive information.
14. Controlled Access Based on Need-to-Know
Enforce least privilege access.
15. Wireless Access Control
Secure and monitor WLAN environments.
Organizational CIS Critical Security Controls (16–20)
The final five controls focus on governance and culture.
16. Account Monitoring and Control
Manage account lifecycles and remove dormant users.
17. Security Awareness and Training
Train employees to recognize and prevent cyber threats.
18. Application Software Security
Secure in-house and third-party applications.
19. Incident Response and Management
Establish a formal, tested incident response plan.
20. Penetration Testing and Red Team Exercises
Simulate attacks to identify weaknesses.
Why the CIS Critical Security Controls Matter
The CIS Critical Security Controls provide:
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A prioritized cybersecurity roadmap
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Alignment with regulatory frameworks
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Practical implementation guidance
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Measurable risk reduction
Organizations that adopt the CIS Controls improve resilience against ransomware, insider threats, and advanced persistent attacks.
Strengthen Your Cybersecurity with Expert Guidance
Implementing the CIS Critical Security Controls correctly requires technical depth and strategic oversight.
RSI Security helps organizations:
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Assess current maturity
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Map controls to compliance frameworks
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Implement and validate safeguards
Contact RSI Security today to strengthen your cybersecurity posture.
Download Our CIS Controls Implementation Checklist