CVA Network Infrastructure & Security Weaknesses 3

Question 1

Which condition makes a network vulnerable to a DHCP starvation attack?

Accepted Answer

No DHCP snooping configured on access layer switches

Answer

Without DHCP snooping, an attacker can flood the DHCP server with requests using spoofed MAC addresses, exhausting the IP address pool and causing denial of service.

Question 2

An assessor finds that an organization uses telnet for out-of-band management of network devices. What is the critical weakness?

Accepted Answer

All management credentials and commands are transmitted in cleartext

Answer

Telnet transmits all data including usernames, passwords, and configuration commands in plaintext, making credentials trivially capturable by any network sniffer.

Question 3

What does the term 'network perimeter erosion' describe in modern vulnerability assessments?

Accepted Answer

The blurring of traditional boundaries due to cloud services, mobile devices, and remote work

Answer

Network perimeter erosion describes how cloud adoption, BYOD, and remote work have dissolved the clear inside/outside network boundary that traditional security models assumed.

Question 4

A vulnerability scan reveals that a network device responds to TCP port 23 and port 22 on its management interface. Which finding should be prioritized?

Accepted Answer

Open Telnet (port 23) because it transmits credentials in cleartext

Answer

Telnet on port 23 is the higher priority finding because any intercepted session immediately exposes plaintext credentials, whereas SSH provides encrypted transport.

Question 5

Which technique allows an attacker to bypass port-based NAC (802.1X) by copying the MAC address of an authenticated device?

Accepted Answer

MAC spoofing / identity theft against 802.1X MAC-based authentication bypass

Answer

MAC-based authentication bypass (MAB) relies solely on MAC address as the credential, which can be trivially spoofed by cloning an authenticated device's MAC address.

(CVA) Certified Vulnerability Assessor Practice Test

(CVA) Certified Vulnerability Assessor Practice Test

CVA Network Infrastructure & Security Weaknesses 3