DCNSA Level II

Network Security flashcards

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Complete Flashcard Reference

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How do security, a vulnerability and an attack relate to one another?

Security: protecting systems, networks and data from unauthorised access, damage or disruption. Vulnerability: a weakness in software, configuration or people that a threat could exploit. Attack: a deliberate attempt to exploit a vulnerability. A vulnerability that is never exploited never becomes an attack; security exists to close it before that happens.

What is the difference between malware and a social engineering attack?

Malware: malicious software (viruses, worms, ransomware, spyware) designed to damage, disrupt or steal from a system. Social engineering: manipulating people, rather than exploiting a technical flaw, into revealing credentials or granting access, through phishing, pretexting and impersonation. No firewall or antivirus stops a user who is convinced to hand over their own password.

What does a firewall do?

It monitors and controls traffic entering and leaving the network based on defined rules. It is the network's first line of defence at its boundary.

How is a risk score worked out for prioritising security findings?

Risk score = Likelihood x Impact, each scored on the same agreed scale, for example 1 to 5. Example: likelihood 3, impact 4 gives 3 x 4 = 12. The highest scores are addressed first.

What is identity and access management (IAM)?

Ensuring every user and system has exactly the access it needs, no more, no less. It is the least-privilege principle applied systematically across every account in the organisation.

What does encryption do, and which two states of data does it protect?

It converts data into a form unreadable without the correct key. It protects data at rest (on disk) and in transit (across the network).

What are the five phases of a penetration test, in order?

1. Planning and reconnaissance 2. Scanning 3. Gaining access 4. Maintaining access 5. Analysis Keep them in strict order, and only ever start with written authorisation and an agreed scope.

What does a network security policy cover, and why does it matter to an auditor?

It is the organisation's written statement of its security rules: acceptable use, password requirements, incident response procedures, data classification and handling. Every deployed control implements it, and an auditor checks the network's actual configuration against it, so a control that contradicts it is itself a finding.

Name the four physical control measures, and why physical controls matter at all.

Access controls, exterior lighting, surveillance, and a perimeter wall or fencing. An attacker with physical access to a server can bypass almost any purely logical control.

Which two Kenyan laws give network security legal weight, and what does each do?

Data Protection Act, 2019: governs personal data, and a breach of it can trigger a reporting duty to the Office of the Data Protection Commissioner. Computer Misuse and Cybercrimes Act, 2018: makes unauthorised access, interference and interception of computer systems criminal offences.

What is access control as a network security control?