Why Prevention Isn’t Enough: How a Second Line of Defense Protects Your Business

by Jan 29, 2025

According to recent reports, cyberattacks rose by 75% in the third quarter of 2024 compared to the same period in the previous year and by 15% compared to the second quarter of 2024. This alarming trend clearly shows that companies are more than ever required to protect their intellectual property, customer data, and reputation.

In today’s interview, Frank Oster, Senior Security Advisor at Nextron Systems, explains why a second line of defense is essential and how companies can benefit from it.

How do you define the first and second line of defense in IT security? 

Frank Oster: The threat landscape has changed significantly. Cybercriminals are becoming more sophisticated and increasingly bypass traditional security mechanisms. The first line of defense consists of technologies such as firewalls, antivirus software, and Endpoint Detection and Response (EDR) systems. These solutions block known threats and prevent unauthorized access.
But what happens when attackers gradually and almost imperceptibly overcome these barriers? This is where the second line of defense comes into play. It detects attackers who have already infiltrated a system and may have been active for an extended period. This approach serves as an additional protective measure and does not replace the solutions of the first line of defense.

What measures are part of the second line of defense?

Frank Oster: The second line of defense includes APT scanners, forensic analysis, and intrusion detection systems. The key difference lies in their approach: While the first line is designed to prevent attacks, the second line focuses on detecting and analyzing threats that have already infiltrated the system. It ensures that no attack goes unnoticed and can be contained quickly. In other words, companies gain crucial time to identify and combat even highly specialized, targeted attacks conducted with significant financial resources.

What role do APT scanners play in this context?

Frank Oster: APT-scanners like THOR are key technologies of the second line of defense. Advanced Persistent Threats (APTs) and other sophisticated attacks intentionally evade traditional security mechanisms and remain undetected for long periods.

An APT scanner searches for indicators of such threats—suspicious log files, obfuscation techniques, or hidden malware. It not only detects known threats using Indicators of Compromise (IOCs) but also identifies suspicious behavior based on YARA and Sigma rules, which may indicate deeply embedded attacks.

Are APT scanners specifically designed to detect targeted attacks?

Frank Oster: Exactly. These scanners identify IOCs and use various techniques to make hidden threats visible. They analyze how deeply an attack has already penetrated the system. This is crucial because the longer a threat remains undetected, the harder it becomes to recognize and eliminate.

Would you recommend integrating APT scanners into a company’s security framework?

Frank Oster: Absolutely. These scanners enable targeted and periodic security assessments to determine whether a company has been compromised.

THOR can be seamlessly integrated with SIEMs, Threat Intelligence platforms (e.g., MISP), and the ASGARD Management Center, enabling centralized management and analysis of results.

These systems identify suspicious activities and document them, allowing incident response teams to react quickly. However, it is important to note that THOR does not provide real-time detection or response like EDR solutions. Instead, it facilitates in-depth forensic analysis, making attacks visible and enabling effective investigations.

What is your ideal security approach?

Frank Oster: A multi-layered security approach is ideal. The first line of defense – including antivirus software, firewalls, and EDR solutions – is essential. However, the second line of defense is just as crucial, as it detects what the first line may have missed. As mentioned earlier, it has become more important than ever for companies to detect and contain attacks before they cause significant damage. Last but not least: Employee awareness remains a critical success factor in the fight against cybercrime.

Is the second line of defense also a tool for damage mitigation?

Frank Oster:  Definitely: It functions like an emergency response team that intervenes when an attack has occurred. Technologies like THOR enable incident response teams to systematically search for attack traces and reconstruct the attack chain. This allows for a faster response and more precise countermeasures.

However, THOR does not stop attacks in real-time but provides valuable insights for damage mitigation and post-attack analysis. In today’s threat landscape, this forensic capability is indispensable for developing robust and resilient security strategies.

Thank you for your insights, Frank Oster.

About the author:

Franziska Ploss

Marketing Lead & Content Creation

Subscribe to our Newsletter

Monthly news, tips and insights.

Follow Us

Upgrade Your Cyber Defense with THOR

Detect hacker activity with the advanced APT scanner THOR. Utilize signature-based detection, YARA rules, anomaly detection, and fileless attack analysis to identify and respond to sophisticated intrusions.