What Is Defense in Depth?

“Defense in depth” (DiD) is a cybersecurity strategy inspired by military strategy, providing multiple layers of security controls to protect enterprise IT systems. Each layer of controls can block or mitigate different types of attacks. which in total makes it much more difficult for attackers to succeed.

Using this strategy can strengthen your organization’s security posture and reduce the risks of successful cyberattacks.

This article will explore why DiD is critical for modern businesses operating in an expanding threat landscape. We will outline the strategy’s benefits and the security elements to consider when implementing defense in depth strategies.

How Defense in Depth Works

The goal of the DiD’s “castle approach” is to slow down an attacker and progressively weaken his or her attack, rather than to defeat the attacker immediately with one strong line of defense – a line of defense that could still fail, and then give the attacker free rein.

DiD treats security as an ongoing process. It relies on the coordinated use of multiple security measures to shore up your defenses and keep hackers out of your security perimeter.

Example 1: You might protect your company website from XSS (cross-site scripting), CSRF (cross-site request forgery), and other types of cyberattacks with DiD that includes:

• Antivirus software
• Web application firewall (WAF)
• Anti-spam software
• Privacy controls

Example 2: To protect your enterprise network with DiD, you might implement:

• Firewalls
• Data encryption
• Intrusion protection system
• Antivirus software

Types of Security Controls in Defense in Depth

The DiD security strategy employs various security control families to protect enterprise assets and sensitive data. For example, DiD controls can also be categorized as:

• Administrative controls. Security policies or procedures to guide and control user behaviors.
• Physical controls. Security guards or locked doors to provide physical security.
• Technical controls. Measures to protect enterprise assets, such as firewalls or antivirus programs.

It’s wise to use different types of controls when designing a DiD system.

Preventive Controls

Preventive controls are meant to stop an attack from happening in the first place. They prevent unauthorized users (internal or external, malicious or inadvertent) from accessing an enterprise system and causing malicious damage or unintentional errors.

Some examples include:

• Firewalls
• Antivirus software
• Malware scanners
• Spam management tools
• Data and device encryption
• Access controls
• Security awareness training
• Penetration testing

Detective Controls

Detective controls are implemented to identify and respond to attacks after the attack has occurred. They are essential to help you investigate security incidents and prevent a recurrence.

Examples include:

• Security event log monitoring
• Host and network intrusion detection systems (IDS)
• Audit trails
• CCTV footage

Corrective Controls

Corrective controls help mitigate the potential impact of a security event and enable organizations to recover to normal operations.

Examples include:

• Business continuity plans
• Disaster recovery plans
• Automatic removal of malware by antivirus software

Importance of Defense in Depth

DiD is vital because its layered, multi-element approach reduces the risk of a successful attack. Even if one layer is breached, the attacker still has to penetrate additional layers of defense before he or she can access your business-critical assets or sensitive information. Each layer provides protection from potentially catastrophic cybersecurity incidents.

Benefits of Defense in Depth

Defense in depth provides several benefits to organizations, including:

Improves Incident Detection and Response

Using multiple layers of security makes it easier to detect and respond to attacks; that helps to minimize damage. It also speeds up recovery time so that you can return to normal operations more quickly.

Strengthens the Overall Security Posture

Multiple security layers also make your organization more secure overall, thus deterring attackers from targeting your company with ransomware, spear phishing, or other types of cyberattacks.

Improves the Compliance Posture

DiD provides additional safeguards and countermeasures that allow you to meet regulatory requirements around data security or privacy, which improves your compliance posture.

Reduce the Cost of Data Breaches

As the average cost of cyberattacks ($133,000 in 2020) and data breaches ($4.24 million in 2021) increases, DiD provides more robust security to prevent such incidents. These additional safeguards can help you save far more money than you would save by using only a single layer of security.

Key Security Elements of Defense in Depth

The critical elements of DiD are:

Network Security Controls

Firewalls and intrusion prevention systems (IPS) are vital security elements in DiD. These security solutions protect the enterprise network from unauthorized or malicious users.

Firewalls can be customized with specific security rules. They then evaluate network traffic against the set baselines to identify and block suspicious traffic. An IPS can also identify and respond to potential cyber threats to prevent a breach.

Antivirus Software

Antivirus software detects and removes viruses from endpoints (such as laptops or printers) and prevents them from causing further damage to that device or other devices on the network.

For optimal security, it’s best to avoid a signature-based antivirus solution since that can be exploited by cybercriminals. Use a heuristic-based solution instead, since it can continually scan for suspicious activities and provide more reliable protection.

Behavioral Analysis

User behavioral analysis (UBA) solutions evaluate user behaviors based on agreed baselines about “normal” behavior. If they detect suspicious activity, they send alerts to the security team or execute automatic controls to contain a breach.

Data Protection

DiD usually incorporates multiple data protection methods, such as:

• Encryption of data at rest
• Encrypted backups
• Hashing
• Source IP address checks

Access Controls

Controlling user access goes a long way towards preventing unauthorized users from entering the enterprise system, accessing its resources, or exfiltrating data. Common access control measures in DiD include:

• Virtual private network (VPN)
• Single sign-on (SSO)
• Multi-factor authentication (MFA) and biometrics

Use ZenGRC to Enhance Your Cybersecurity

A robust defense in depth strategy can help defend your organization from many types of attack vectors and threat actors. Strengthen this plan with detailed visibility into your cybersecurity environment. Get deep insights into the threats and risks affecting your assets and data with ZenGRC.

Security policies, incident response procedures, and internal controls must be documented and updated regularly to ensure they meet the evolving cybersecurity environment. With ZenGRC’s document repository, policies and procedures are revision-controlled and easy to find.

Workflow management features offer easy tracking, automated reminders, and audit trails. The ZenConnect feature enables integration with popular tools, such as Jira, ServiceNow, and Slack, ensuring seamless adoption within your enterprise.

ZenGRC provides a holistic and detailed view of your enterprise risks, vulnerabilities, and threats from one integrated platform. Leverage its risk heatmaps, risk catalog, and dashboards to address cybersecurity risk, remediate security incidents in real-time, and minimize damage. Add ZenGRC to your cybersecurity checklist today!

Schedule a demo of ZenGRC to understand how it can help strengthen your cybersecurity program.