ISACA Certified Information Systems Auditor (CISA) ExamDomain 5: Protection of Information AssetsMedium
A CISA is reviewing the network security architecture of an organization. The organization has implemented a robust firewall and an intrusion prevention system (IPS) at its network perimeter. However, the CISA notes that there is no internal network segmentation, and all servers and workstations reside on a flat network. What is the MOST significant risk introduced by this flat network architecture?
- AHigher likelihood of Denial-of-Service (DoS) attacks impacting critical internal systems.
- BRapid lateral movement of an attacker or malware across the entire internal network.
- CInability to accurately monitor network traffic for anomalous behavior.
- DIncreased difficulty in applying security patches to all network devices uniformly.
Show answer & explanationAnswer & explanation
Correct answer: B. Rapid lateral movement of an attacker or malware across the entire internal network.
A flat network, without internal segmentation, provides no barriers once an attacker or malware breaches the perimeter defenses (firewall, IPS). This allows for rapid and unhindered lateral movement across the entire internal network, granting an attacker easy access to other systems, sensitive data, and the ability to escalate privileges, making it the most significant risk.
Why the other options are wrong
- A. While DoS attacks can be impactful, a flat network primarily facilitates internal spread post-breach, rather than directly increasing the likelihood of DoS from external sources.
- C. Monitoring can still be done, but a flat network makes it harder to *isolate* anomalous behavior to a specific segment and prevent its spread.
- D. Patching difficulty is a management challenge, not the most significant security risk of a flat network's inherent design flaws.
Network Segmentation (Internal)
Dividing a network into smaller, isolated sub-networks (segments) to restrict traffic flow and limit the impact of security breaches.
- Prevents lateral movement of attackers and malware.
- Enforces the principle of least privilege for network communication.
- Crucial for containing breaches and protecting critical assets.
Memory trick: A 'FLAT' network lets attackers 'SLIDE' everywhere.