SecurityX CAS-005 Book

Zero Trust security is based on the principle of “never trust, always verify.” For a mobile and frequently traveling workforce, enforcing rigid access models without adaptability creates friction and hampers productivity. The first priority in Zero Trust design for such a workforce is to deploy context-aware reauthentication combined with User Behavior Analytics (UBA). This ensures that deviations from baseline user behavior—such as unusual geographic access, time of day anomalies, or device changes—trigger additional authentication or session restrictions.

Option A (hardware OTPs) enhances authentication security but does not provide adaptive, risk-based controls for varying user behavior. Option B (TLS decryption) focuses on network traffic inspection, which is important but secondary to ensuring identity and access enforcement in a Zero Trust model. Option C (posture compliance checks) is necessary but typically part of ongoing device security enforcement rather than the initial step.

By starting with context-aware reauthentication, the organization ensures its Zero Trust strategy adapts dynamically to user behavior, providing both stronger security and a smoother experience for a global, remote workforce.

SecurityX CAS-005 network architecture objectives emphasize limiting exposure of vulnerable systems by using application-aware firewalls with strict rule sets.

This approach directly reduces the attack surface by allowing only approved application traffic to and from the vulnerable systems, mitigating risk until systems are patched or replaced.

EDR (A) enhances detection but doesn’t inherently reduce the exposed services.

Network segmentation in monitor mode (B) doesn’t block threats.

IDS (C) detects activity but does not block it.

In the given scenario, the security engineer is likely examining login activities and their associated geolocations. This type of analysis is aimed at identifying unusual login patterns that might indicate an impossible travel scenario. An impossible travel scenario is when a single user account logs in from geographically distant locations in a short time, which is physically impossible. By assessing login activities using geolocation, the engineer can tune alerts to identify and respond to potential security breaches more effectively.

The SIEM already contains multiple events that, if correlated, would have indicated an active attack sequence on VM001—such as denied connections, IPS alerts, malware detection, and then an allowed connection. CAS-005 Security Operations objectives emphasize log correlation as a way to enhance detection by linking related events across different time stamps and data sources into a single, higher-confidence alert.

Option A (adding EDR logs) could add visibility but does not address the need to connect existing events for earlier detection.

Option C (improving parsing) ensures readability but does not create actionable alerts.

Option D (creating a new malware detection rule) is redundant since malware detection already appeared in logs; the issue was the lack of correlation to act on it in time.

By correlating IDS, IPS, firewall, and malware detection logs, the SIEM can raise a higher-priority alert before the attack is completed.