ISC2 CC Network Security Practice Question
During a security assessment, a penetration tester captures network traffic and notices that the source IP address in packets appears to be from a different network. Which technique is the attacker likely using?
⚠ Common exam trap
A common mix-up: candidates confuse Layer 2 address manipulation (ARP/MAC spoofing) with Layer 3 source-address forgery (IP spoofing) — the question's phrase 'source IP address' is the decisive clue.
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
✓
IP spoofing
IP spoofing involves forging the source IP address field in packet headers so the traffic appears to originate from a different network or host. The scenario explicitly describes source IP addresses appearing to come from a different network, which is the defining symptom of IP spoofing. Attackers use it for reflection/amplification DDoS, evasion, and impersonation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
DNS spoofing
Why it's wrong here
DNS spoofing forges name-resolution replies, redirecting clients to attacker-controlled addresses; it does not rewrite the source IP field inside captured packets. It is tempting because spoofing appears in the question, but IP source address falsification is IP spoofing, a distinct technique operating at the network layer.
- ✗
ARP spoofing
Why it's wrong here
ARP spoofing poisons the local Layer 2 ARP cache, mapping a victim's IP to the attacker's MAC within the same broadcast domain; it cannot rewrite the source IP to appear from a different network. It is tempting because ARP spoofing enables on-path interception, which would be the right answer if traffic were being redirected rather than re-addressed.
- ✗
MAC spoofing
Why it's wrong here
MAC spoofing alters the layer-2 hardware address in Ethernet frames, leaving the layer-3 source IP unchanged, so captured packets would not show a foreign network address. It is tempting because both are spoofing techniques, but only IP spoofing falsifies the source IP address observed in traffic.
- ✓
IP spoofing
Why this is correct
IP spoofing forges the source address field in packet headers so traffic appears to originate from a different network, matching the observed foreign source addresses. It is distinct from MAC spoofing, which alters Layer 2 addresses.
Go deeper
Related to this question
Learn chapter
Network Security Components and Controls
Key term
Impersonation
Impersonation is a security attack where an attacker pretends to be a legitimate person or system to gain unauthorized access, steal data, or commit fraud.
Key term
DDoS
A DDoS (Distributed Denial-of-Service) attack is a malicious attempt to disrupt normal traffic of a targeted server, service, or network by overwhelming it with a flood of internet traffic from multiple compromised systems.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official ISC2 exam blueprint
This CC 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 CC exam.