hardMultiple Choice
SSCP Practice Question: Configures a VLAN hopping attack prevention by…
A network engineer configures a VLAN hopping attack prevention by setting all unused switch ports to an unused VLAN and disabling trunking. What vulnerability is being mitigated?
⚠ Common exam trap
ISC2 often tests the distinction between DTP spoofing (VLAN hopping via trunk negotiation) and double-tagging attacks (another VLAN hopping method), so candidates may confuse the two or incorrectly associate VLAN hopping with MAC flooding or ARP spoofing.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
DTP spoofing
DTP spoofing is the correct answer because VLAN hopping attacks often exploit Dynamic Trunking Protocol (DTP) to negotiate a trunk link between a switch and an attacker's device, allowing the attacker to send and receive traffic on multiple VLANs. By disabling trunking on all unused ports and assigning them to an unused VLAN, the switch will not respond to DTP negotiation requests, preventing unauthorized trunk establishment.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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STP manipulation
Why it's wrong here
STP manipulation involves forging superior BPDUs to become root; the described hardening addresses switchport trunk negotiation abuse, not BPDU Guard or Root Guard. It is tempting because both are Layer 2 switch protections commonly deployed together on access ports.
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ARP spoofing
Why it's wrong here
ARP spoofing poisons the IP-to-MAC mapping cache; unused-port VLAN assignment and trunk disabling do not authenticate ARP replies. It is tempting because Dynamic ARP Inspection, frequently enabled with DHCP snooping on the same access switches, is the actual countermeasure.
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MAC flooding
Why it's wrong here
MAC flooding overflows the CAM table so frames flood everywhere; the described configuration restricts trunk formation, not source-MAC learning limits. It is tempting because Port Security, often configured on the same unused access ports, is the actual mitigation for MAC flooding.
- ✓
DTP spoofing
Why this is correct
DTP spoofing lets an attacker negotiate a trunk link from an access port, gaining access to all VLANs. Setting unused ports to an unused VLAN and disabling trunking (switchport nonegotiate) blocks DTP frame exchange, preventing the rogue trunk from forming and stopping VLAN hopping.
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DHCP starvation
Why it's wrong here
DHCP starvation exhausts a server's address pool through forged DISCOVER requests; unused-port VLAN assignment and trunk disabling do nothing to rate-limit or authenticate DHCP traffic. It is tempting because DHCP snooping, often configured alongside these hardening steps, is the actual mitigation for starvation.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SSCP practice question is part of Courseiva's free ISC2 certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SSCP exam.