CompTIA CAS-005 - CompTIA SecurityX Certification Exam

Analysis and Remediation Options for Each IoC:

IoC 1:

Evidence:

Source: Apache_httpd

Type: DNSQ

Dest: @10.1.1.1:53,@10.1.2.5

Data: update.s.domain, CNAME 3a129sk219r9slmfkzzz000.s.domain, 108.158.253.253

Analysis:

Analysis: The service is attempting to resolve a malicious domain.

Reason: The DNS queries and the nature of the CNAME resolution indicate that the service is trying to resolve potentially harmful domains, which is a common tactic used by malware to connect to command-and-control servers.

Remediation:

Remediation: Implement a blocklist for known malicious ports.

Reason: Blocking known malicious domains at the DNS level prevents the resolution of harmful domains, thereby protecting the network from potential connections to malicious servers.

IoC 2:

Evidence:

Src: 10.0.5.5

Dst: 10.1.2.1, 10.1.2.2, 10.1.2.3, 10.1.2.4, 10.1.2.5

Proto: IP_ICMP

Data: ECHO

Action: Drop

Analysis:

Analysis: Someone is footprinting a network subnet.

Reason: The repeated ICMP ECHO requests to different addresses within a subnet indicate that someone is scanning the network to discover active hosts, a common reconnaissance technique used by attackers.

Remediation:

Remediation: Block ping requests across the WAN interface.

Reason: Blocking ICMP ECHO requests on the WAN interface can prevent attackers from using ping sweeps to gather information about the network topology and active devices.

IoC 3:

Evidence:

Proxylog:

GET /announce?info_hash=%01dff%27f%21%10%c5%wp%4e%1d%6f%63%3c%49%6d&peer_id%3dxJFS

Uploaded=0&downloaded=0&left=3767869&compact=1&ip=10.5.1.26&event=started

User-Agent: RAZA 2.1.0.0

Host: localhost

Connection: Keep-Alive

HTTP200 OK

Analysis:

Analysis: An employee is using P2P services to download files.

Reason: The HTTP GET request with parameters related to a BitTorrent client indicates that the employee is using peer-to-peer (P2P) services, which can lead to unauthorized data transfer and potential security risks.

Remediation:

Remediation: Enforce endpoint controls on third-party software installations.

Reason: By enforcing strict endpoint controls, you can prevent the installation and use of unauthorized software, such as P2P clients, thereby mitigating the risk of data leaks and other security threats associated with such applications.

Microsegmentation is a critical strategy within Zero Trust architecture that enhances context-aware access systems by dividing the network into smaller, isolated segments. This reduces the attack surface and limits lateral movement of attackers within the network. It ensures that even if one segment is compromised, the attacker cannot easily access other segments. This granular approach to network security is essential for enforcing strict access controls and monitoring within Zero Trust environments.

To prevent sensitive corporate information from being exposed if a laptop is stolen, the solution must ensure that data is not stored locally and access is tightly controlled. According to the CompTIA SecurityX CAS-005 study guide (Domain 4: Governance, Risk, and Compliance, 4.3), Desktop as a Service (DaaS) hosts data and applications in the cloud, reducing the risk of data exposure on physical devices. Combining DaaS with multifactor authentication (MFA) ensures that even if a laptop is stolen, unauthorized access to the cloud environment is prevented.

Option B:IP allow lists and SSO do not address data stored locally on the laptop, which could be accessed offline.

Option C:MDM and stronger passwords help but do not prevent data exposure if the device is compromised (e.g., via offline attacks).

Option D:Updating policies and monitoring breaches are reactive measures that do not directly protect data on a stolen laptop.

Option A:DaaS ensures no sensitive data resides on the device, and MFA secures access, making it the best solution.

Tokenization replaces sensitive data elements with non-sensitive equivalents, called tokens, that can be used within the internal tests. The original data is stored securely and can be retrieved if necessary. This approach allows the software development team to work with data that appears realistic and valid without exposing the actual sensitive information.

Configuring data hashing (Option A) is not suitable for test data as ittransforms the data into a fixed-length value that is not usable in the same way as the original data. Replacing data with null records (Option C) is not useful as it does not provide valid data for testing. Data obfuscation (Option D) could be an alternative but might not meet the regulatory requirements as effectively as tokenization.

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.

Understanding Business Impact Analysis (BIA):

ABIA assesses the effects of disruptionsto an organization's operations.

It helpsprioritize resourcesbased on the potential impact ofdowntime, compliance issues, and critical processes.

Why Options B, C, and F are Correct:

B (Applicable contract obligations)→ Many companies havelegal and compliance obligationsregarding downtime, availability, and SLAs. This information helps determine whatrisk levelsare acceptable.

C (Costs associated with downtime)→ BIA quantifies the financial impact of system failures. Knowinglost revenue, regulatory fines, and recovery costshelps in planning.

F (Critical processes)→ Identifyingcore business processesallows an organization toprioritize recoveryeffortsandmaintain operational continuity.

Why Other Options Are Incorrect:

A (Inventory details)→ While useful for asset management, it doesnot directly impact business continuity planning.

D (Network diagrams)→ These help in security architecture but arenot directly related to the financial/business impact analysis.

E (Contingency plans)→ BIA isperformed before contingency planningto identifywhat needs protection.

Attack surface reductionfocuses on minimizingunnecessary services, open ports, and vulnerabilities, reducing the exposure to potential adversaries. This aligns withzero trust and least privilege principles.

Secure Boot (A)helps ensure system integrity but does not minimize exposed services.

Disabling third-party integrations (C)may help, but broader attack surface reduction is the best first step.

Limiting access (D)is important but does not directly reduce exposed services.

To design resilience in an enterprise system that can survive environmental catastrophes, recover within 24 hours, and be resilient to active exploitation, the best strategy is to allocate fully redundant and geographically distributed standby sites. Here’s why:

Geographical Redundancy: Having geographically distributed standby sites ensures that if one site is affected by an environmental catastrophe, the other sites can take over, providing continuity of operations.

Full Redundancy: Fully redundant sites mean that all critical systems and data are replicated, enabling quick recovery in the event of a critical loss of availability.

Resilience to Exploitation: Distributing resources across multiple sites reduces the risk of a single point of failure and increases resilience against targeted attacks.

To prevent unauthorized applications from running, the company needs a mechanism to explicitly define and enforce which applications are allowed to execute. "Permit listing" (often referred to as "whitelisting" in security contexts) is the most effective solution here. It involves creating a list of approved applications, and only those on the list are permitted to run, blocking all others by default. This directly addresses the root cause—users installing unapproved software—by restricting execution to only authorized programs.

Option A (Signing):Code signing ensures the authenticity and integrity of software by verifying it comes from a trusted source and hasn’t been tampered with. While useful, it doesn’t inherently prevent unauthorized applications from running unless combined with a policy like whitelisting.

Option B (Access control):Access control governs who can access systems or resources but doesn’t specifically restrict which applications can execute. It’s too broad for this scenario.

Option C (HIPS):A Host-based Intrusion Prevention System (HIPS) can detect and block malicious behavior, but it’s reactive and relies on signatures or heuristics, not a proactive allow-only approach.

Option D (Permit listing):This is the best fit, as it proactively enforces a policy where only explicitly authorized applications can run, preventing malware introduced by unauthorized software.