CompTIA CAS-005 - CompTIA SecurityX Certification Exam

When differentiating between valid and invalid findings from vulnerability scans, the systemsadministrator should verify that the scanning credentials are properly configured. Valid credentials ensure that the scanner can authenticate and access the systems being evaluated, providing accurate and comprehensive results. Without proper credentials, scans may miss vulnerabilities or generate false positives, making it difficult to prioritize and address the findings effectively.

Homomorphic encryption allows computations to be performed on encrypted data without decrypting it, preserving confidentiality. However, its adoption faces significant challenges due to performance overhead. According to the CompTIA SecurityX CAS-005 study materials (Domain 3: Cybersecurity Technology, 3.3), homomorphic encryption requires substantial computational resources, which standard processors struggle to provide efficiently. Specialized hardware, such as coprocessors (e.g., GPUs or TPUs), is oftenneeded to handle the complex mathematical operations involved. The lack of widespread, optimized coprocessor support in existing infrastructure is a primary barrier to adoption.

Option A (Incomplete mathematical primitives):While early homomorphic encryption schemes had limitations, modern schemes (e.g., CKKS, BFV) have mature mathematical foundations, making this less of a challenge today.

Option B (No use cases):Use cases exist, such as secure cloud computing and privacy-preserving data analytics, so this is not accurate.

Option C (Quantum computers):Homomorphic encryption is not dependent on quantum computing, and quantum computers are unrelated to its current challenges.

Option D (Insufficient coprocessor support):This is the most accurate, as performance bottlenecks require specialized hardware that is not yet widely available or integrated.

HMAC (Hash-based Message Authentication Code)ensures the integrity and authentication of API requests without exposing static or hard-coded private keys. It uses a secret key and a hash function, preventing replay attacks and tampering. VPNs secure the transport layer, MFA protects user accounts (not API-to-database communications), and DSA is a signature algorithm but does not address hard-coding risk directly.

The data provided shows that all companies have SIEM systems, but they differ in their implementation of UEBA, DLP, ISAC membership, and TIP integration. The key metric to evaluate is the effectiveness in detecting and responding to attacks, as shown by the "Time to Detect" and "Time to Respond" columns. Company 1, which is an ISAC member, has the fastest detection (10 minutes) and response (20 minutes) times. Company 3, which is not an ISAC member, has slower detection (12 minutes) and response (24 minutes) times, despite having UEBA and TIP integration. Company 2, which lacks TIP integration but is an ISAC member, has the slowest times (20 minutes to detect, 40 minutes to respond). This suggests that ISAC membership correlates with faster detection and response, likely due to access to shared threat intelligence.

According to the CompTIA SecurityX CAS-005 objectives (Domain 2: Security Operations, 2.2), Information Sharing and Analysis Centers (ISACs) are critical for enabling organizations to share real-timethreat intelligence within their industry. ISACs provide access to actionable intelligence, best practices, and coordinated response strategies, which are essential for defending against sophisticated attacks targeting critical infrastructure like the energy sector. The lack of ISAC membership (Company 3) limits access to this intelligence, hindering proactive defense and response capabilities. While UEBA, DLP, and TIP integration are valuable, they are more focused on internal monitoring, data protection,and individual threat intelligence feeds, respectively, and do not provide the same industry-wide collaboration as an ISAC.

The scenario describes a sophisticated attack where the threat actor used steganography within LDAP to exfiltrate data. Given that thehardware and OS firmware were validated and found uncompromised, the attack vector likely exploited a network communication channel. To mitigate such risks, enforcing allow lists for authorized network ports and protocols is the most effective strategy.

Here’s why this option is optimal:

Port and Protocol Restrictions: By creating an allow list, the organization can restrict communications to only those ports and protocols that are necessary for legitimate business operations. This reduces the attack surface by preventing unauthorized or unusual traffic.

Network Segmentation: Enforcing such rules helps in segmenting the network and ensuring that only approved communications occur, which is critical in preventing data exfiltration methods like steganography.

Preventing Unauthorized Access: Allow lists ensure that only predefined, trusted connections are allowed, blocking potential paths that attackers could use to infiltrate or exfiltrate data.

Other options, while beneficial in different contexts, are not directly addressing the network communication threat:

B. Measuring and attesting to the entire boot chain: While this improves system integrity, it doesn’t directly mitigate the risk of data exfiltration through network channels.

C. Rolling thecryptographic keys used for hardware security modules: This is useful for securing data and communications but doesn’t directly address the specific method of exfiltration described.

D. Using code signing to verify the source of OS updates: Ensures updates are from legitimate sources, but it doesn’t mitigate the risk of network-based data exfiltration.

Excessive MFA push notifications can be a sign of an attempted push notification attack, where attackers repeatedly send MFA prompts hoping the user will eventually approve one by mistake. To mitigate this:

A. Provisioning FIDO2 devices: While FIDO2 devices offer strong authentication, they may not be practical for all users and do not directly address the issue of excessive push notifications.

B. Deploying a text message-based MFA: SMS-based MFA can still be vulnerable to similar spamming attacks and phishing.

C. Enabling OTP via email: Email-based OTPs add another layer of security but do not directly solve the issue of excessive notifications.

D. Configuring prompt-driven MFA: This option allows users to respond to prompts in a secure manner, often including features like time-limited approval windows, additional verification steps, or requiring specificactions to approve. This can help prevent users from accidentally approving malicious attempts.

Configuring prompt-driven MFA is the best solution to restrict unnecessary MFA notifications and improve security.

The output indicates that the software tool contains hard-coded credentials, which attackers can exploit to bypass user access controls and load the database. The mostlikely recommendation is to remove hard-coded credentials from the source code. Here’s why:

Security Best Practices: Hard-coded credentials are a significant security risk because they can be easily discovered through reverse engineering or simple inspection of the code. Removing them reduces the risk of unauthorized access.

Credential Management: Credentials should be managed securely using environment variables, secure vaults, or configuration management tools that provide encryption and access controls.

Mitigation of Exploits: By eliminating hard-coded credentials, the organization can prevent attackers from easily bypassing authentication mechanisms and gaining unauthorized access to sensitive systems.

Sinkholing, or DNS sinkholing, is a method used to redirect malicious traffic to a safe destination. This technique is often employed by security teams to prevent access to malicious domains by substituting a benign destination IP address.

In the given logs, users from the finance department are accessing www.bank.com and receiving HTTP status code 495. This status code is typically indicative of a client certificate error, which can occur if the DNS traffic is being manipulated or redirected incorrectly. The consistency in receiving the same HTTP status code across different users suggests a systematic issue rather than an isolated incident.

Recursive DNS resolution failure (A) would generally lead to inability to resolve DNS at all, not to a specific HTTP error.

DNS poisoning (B) could result in usersbeing directed to malicious sites, but again, would likely result in a different set of errors or unusual activity.

Incorrect DNS setup (D) would likely cause broader resolution issues rather than targeted errors like the one seen here.

By reviewing the provided data, it is evident that the DNS traffic for www.bank.com is being rerouted improperly, resulting in consistent HTTP 495 errors for the finance department users. Hence, the most likely cause is that the DNS traffic is being sinkholed.

Animmutable databasepreventsmodifications or deletions, ensuring resilience against ransomware while maintaining multiple copies of data.

Removing unnecessary services from existing endpoints reduces the attack surface by minimizing the number of potential vulnerabilities attackers could exploit. This is a cost-effective method to harden devices without requiring new purchases, aligning perfectly with a purchasing freeze. Deploying new EDR solutions or disposing of devices would likely conflict with the resource freeze, and reimaging systems does not address minimizing services proactively.