hardMultiple ChoiceObjective-mapped
ISC2 CC Practice Question: Is reviewing logs and notices that an internal…
A security engineer is reviewing logs and notices that an internal server is receiving excessive SYN packets from an external IP, but never completing the three-way handshake. What type of attack is likely occurring?
⚠ Common exam trap
ISC2 often tests the distinction between attacks that use ICMP (Smurf, Ping of death) versus TCP (SYN flood), so candidates may confuse the protocol layer or misremember that a Smurf attack involves SYN packets instead of ICMP echo requests.
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
✓
SYN flood
A SYN flood attack exploits the TCP three-way handshake by sending a high volume of SYN packets to a target server without completing the handshake (i.e., not sending the final ACK). This exhausts the server's connection table resources, preventing legitimate connections. The log evidence—excessive SYN packets from an external IP with no handshake completion—is the classic signature of a SYN flood.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Smurf attack
Why it's wrong here
Smurf attack uses ICMP broadcast amplification.
- ✗
Ping of death
Why it's wrong here
Ping of death involves oversized ICMP packets.
- ✗
ARP poisoning
Why it's wrong here
ARP poisoning maps IPs to MAC addresses locally.
- ✓
SYN flood
Why this is correct
SYN flood sends many SYN packets, leaving half-open connections.
Visual reference
Go deeper
Related to this question
Learn chapter
Introduction to Security Principles
Key term
Denial-of-service
A Denial-of-service (DoS) attack is an attempt to make a computer, network, or online service unavailable to its intended users by overwhelming it with fake traffic or requests.
Key term
TCP
TCP is a connection-oriented transport layer protocol that ensures reliable, ordered, and error-checked delivery of data between applications over IP networks.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.