CAS-005 Exam Dumps : CompTIA SecurityX Certification Exam

The best answer is B. An attacker viewed password hashes on the device . The decisive event is sudo cat /etc/shadow SUCCESS . On Linux systems, /etc/shadow stores password hashes and related account password data. The log therefore indicates successful privileged access to that file and successful viewing of its contents. CompTIA’s SecurityX Security Operations domain includes analysis of indicators of malicious activity and investigation of suspicious system behavior; this command sequence is consistent with credential-access activity.

Why the other options are not best:

A is incorrect because there is no evidence of file injection. C is not supported because the logs show file access, not confirmed data transfer or exfiltration. D is tempting because of cd ../../ , but that is only navigation. The key security-relevant action is the successful reading of /etc/shadow , which means password hashes were viewed.

The best solution is to implement authentication for API requests and apply appropriate rate limiting (C). Authentication ensures that only authorized customers or systems can access the API, while rate limiting helps prevent denial-of-service (DoS)-like conditions and cost inflation from excessive or malicious requests. This addresses both the security (unauthorized access) and cost issues (serverless billing based on execution).

Option A (digital certificates) is a strong control for authentication but may introduce unnecessary complexity and does not address rate abuse directly. Option B (rate limits with IP reputation checks) is useful but insufficient—malicious actors may rotate through new IPs not yet flagged. Option D (regional restrictions) might reduce some noise traffic but risks blocking legitimate global users and is not scalable for a modern cloud service.

CAS-005 highlights securing APIs with authentication, authorization, and throttling as best practices. Thus, the combined approach of API authentication plus rate limiting is the most comprehensive and effective solution.

To meet the requirements of having allendpoints establish telemetry with a SIEM, integrate into an XDR platform, and allow SOC services to monitor the XDR platform, the best approach is to implement Host Intrusion Prevention Systems (HIPS) and a host-based firewall. HIPS can provide detailed telemetry data to the SIEM and can be integrated into the XDR platform for comprehensive monitoring and response. The host-based firewall ensures that only authorized traffic is allowed, providing an additional layer of security.