Why MDR is the Missing Link in Cyber Defense

Endpoint Detection and Response (EDR) is often a crucial part of a company's cyber defense, helping security teams detect and counter advanced persistent threats (APTs) and hidden attacks.

EDR agents gather telemetry data from workstations, servers, and other assets. This raw data is sent to a processing server, where it is analyzed and then delivered to security operations center (SOC) specialists in real time via infographics, alerts, and notifications.

In a layered defense strategy, it is crucial to assume that attackers will exploit every possible method to bypass network security measures. When this happens, a modern EDR can detect key attack markers such as log clearing, privilege escalation, and the creation of new accounts within the client OS. While EDR agents effectively collect these indicators, the real question is whether a human specialist will recognize the attack in time.

The Hidden Gaps in EDR Security

EDR is highly effective at detecting complex and sophisticated endpoint attacks, but it has its limitations. One major challenge is that many companies lack the resources—whether due to budget constraints or a shortage of skilled cybersecurity professionals—to build and maintain a full-scale SOC.

SOC specialists focus on analyzing telemetry data, investigating alerts in real time, identifying unusual behavior patterns, and implementing proactive security measures to prevent potential threats.

It is essential to distinguish EDR from SIEM systems, which are more established in the market. Companies generally understand the skill set required for SIEM, including broad IT and network knowledge, as well as incident investigation experience. In contrast, EDR requires more specialized expertise in operating system administration and application security.

To address resource and skill shortages while accelerating incident response, many companies are turning to Managed Detection and Response (MDR)— a service that effectively detects and responds to cyber threats in real time.

MDR Explained

MDR combines EDR with expert-driven threat monitoring and response. It provides continuous infrastructure monitoring, detects incidents, and, in some cases, actively responds to attacks while offering support during security events.

MDR is explicitly designed for telemetry-driven incident investigation. It analyzes data from various sources, including OS logs, user privileges, registry changes, network connections, email activity and attachment hashes, as well as detailed software behavior and artifacts from multimedia content, which can reveal deepfakes used in social engineering attacks.

MDR is typically used by organizations facing staff or skill shortages. Security team members often juggle multiple roles, including technical support and maintaining existing systems, leaving little time for in-depth investigation of EDR alerts.

EDR systems often generate large volumes of false positives—sometimes tens of thousands daily in large organizations. Meanwhile, advanced threats like APTs remain well-hidden, with attackers mimicking legitimate user behavior, including that of administrators. MDR not only collects telemetry but also processes it effectively to identify real threats.

Several MDR solutions are available on the market, typically operating similarly. Telemetry from endpoint agents is sent to the SOC for processing and analysis. Both vendor and customer specialists can access a centralized management console via a web interface.

Core Features of MDR

• Automated Threat Detection – Identifies and analyzes threats in real time.
• 24/7 Monitoring and Incident Response – Ensures continuous security oversight.
• Centralized Management Console – Provides dashboards, infographics, and reports.
• Automated Response Scenarios – Supports countermeasures with minimal manual intervention.
• Asset and Security System Monitoring – Verifies system integrity and availability.
• Threat Intelligence Integration – Offers access to up-to-date cyber threat insights.
• Expert Incident Support – Delivers in-depth analysis and resolution guidance.
• API Integration – Enables seamless data export to external security systems.
• Incident Commenting & Collaboration – Allows for detailed investigation notes.
• Multi-Tenancy Support – Manages security across multiple environments.

Advantages of MDR

• Developer-Driven Security and Threat Intelligence

The most effective users of any cybersecurity tool are its developers, as they understand its intricacies. Analysts trained by developers are best equipped to analyze telemetry, optimize tools and fine-tune them before they are fully refined for widespread use, minimizing false positives.

For high-quality and efficient service, it is desirable to use a large vendor with a robust suite of security products and a dedicated threat research center. The research center continuously updates signature data, tracks evolving threats, and specializes in securing IT systems across various industries and sectors.

• 24/7 Monitoring

Another important feature is 24/7 monitoring, which can be challenging to implement even with mature information security processes: employees may be distracted by another task, go on vacation, become ill, or face another unforeseen circumstance.

• The Power of Security Ecosystems

A key advantage of the ecosystem approach is its ability to integrate data from multiple security tools. This enables MDR within the SOC to detect a broader range of threats by analyzing event data from various sources.

An integrated ecosystem simplifies product support and deployment. For example, some Managed Detection and Response solutions eliminate the need for separate agent installations. Activation can be performed directly through settings if an existing ecosystem product is already installed on the host. Some of the largest antivirus companies now offer MDR, leveraging their existing tools, expertise, and infrastructure.

• Advanced Tools for Precise Detection

Processing telemetry from EDR often leads to a high number of false positives. Vendors leverage cutting-edge technologies, including Machine Learning, to enhance telemetry processing from EDR. Vendor engineers, with direct access to tool developers, are best equipped to manage this challenge by fine-tuning configurations to match the specific security landscape.

MDR Limitations

• Cost

The cost of MDR can be high and varies based on factors such as the number of protected hosts, analyst salaries, electricity expenses, and server room rental. In contrast, EDR typically has a lower cost but requires in-house expertise to manage effectively.

The vendor provides not just a tool but also expert-driven attack detection capabilities. The total cost of owning an EDR includes licensing fees, server infrastructure expenses, and salaries for in-house security analysts. Each organization must assess its specific needs and resources to determine whether EDR or MDR is the better choice.

• False Positives

As mentioned earlier, analysts utilize specialized tools to identify correlations in telemetry and enhance their investigations. MDR engineers in the SOC may deal with false positives, just like in a local EDR system. However, this process remains transparent to the customer, with results presented in a clear and actionable format.

Like many security tools, their agents can flag network scanners, unusual user behavior, or software activity as potential threats. To reduce false positives, proper configuration is necessary, such as adding trusted IP addresses to exceptions or whitelisting approved software.

Case Examples of MDR in Action

Case 1: Human Oversight Catches a Well-Disguised Attack

An attacker successfully gained access to a company's VPN using stolen credentials. While the EDR system flagged unusual activity, the alert was buried among thousands of other daily notifications. The breach remained undetected until an MDR analyst spotted an anomaly—a device connecting to the VPN had a hostname matching a well-known offensive security OS, Kali Linux.

Upon further investigation, the analyst found that the attacker was not only accessing internal resources but had also created new accounts with elevated privileges. Since EDR alone might not have prioritized this as an active attack, the human element in MDR played a critical role in catching and stopping the intrusion before sensitive data could be exfiltrated.

Case 2: MDR Detects a Stealthy Attempt to Cover Tracks

In another case, an attacker who had gained access to a corporate workstation used a specialized tool to wipe USB device connection history from the registry—an action often overlooked by automated detection systems. While EDR logged this event, it did not flag it as suspicious, assuming it was regular administrative activity.

However, an MDR SOC analyst reviewing telemetry noticed a pattern—this registry-clearing tool was executed just minutes after an unauthorized USB device was plugged in. The analyst correlated this with other system logs and discovered that the attacker had used a rogue USB device to introduce malware. Like in the previous case, thanks to MDR's expert-driven analysis, the breach was identified and contained, and the affected system was isolated before any data was exfiltrated.

Case 3: Ecosystem Approach Prevents an Email-Borne Malware Attack

Another company using EDR detected an unusual file download but did not flag it as malicious. However, because the company had a seamlessly integrated MDR ecosystem, the alert was cross-referenced with other security tools, including a sandbox solution that automatically detonates and analyzes suspicious files.

The sandbox flagged the attachment as a Trojan designed to establish a persistent backdoor. Interestingly, the malware targeted IoT devices and mobile applications using MQTT Android for real-time data exchange. Attackers wanted to leverage the MQTT protocol's lightweight architecture to exfiltrate sensitive data from compromised mobile endpoints, making the breach particularly dangerous.

MDR analysts identified the risk and coordinated an automated response—blocking the sender's email domain, quarantining affected endpoints, and notifying the security team. Without MDR's ecosystem-wide correlation, the attack could have slipped through unnoticed.

Case 4: Proactive Recommendations from MDR Specialists

A large enterprise experienced repeated network port scanning attempts targeting specific ports used for online fax services, networked fax machines, and RAW printing. While EDR detected the activity, it lacked context—was this a penetration test, a misconfigured internal tool, or an actual attack?

The MDR team correlated telemetry data, identifying the source as an external IP address previously associated with botnet activity. The SOC team recommended blocking the IP range, enhancing firewall rules, and monitoring for further reconnaissance attempts.

Additionally, MDR specialists suggested proactive security hardening, such as:

• Restricting unnecessary open ports to limit exposure.
• Implementing stricter access controls for sensitive services.
• Conducting regular network scans to identify and address misconfigurations.

Conclusion

This article highlights the key differences between EDR and MDR. As the case studies show, human expertise remains essential for continuous security. While automation can handle routine tasks and process raw telemetry, there comes a point where skilled analysts are needed to effectively detect and investigate anomalies.

Companies often struggle to decide whether to develop in-house cybersecurity expertise or rely on a SOC provider. The choice depends on a detailed cost-benefit analysis of EDR ownership versus MDR services.

Customers often opt for MDR due to the large number of hosts that require protection. The primary driver for this choice is typically a lack of in-house cybersecurity expertise needed to manage and protect their systems effectively.