A penetration tester was assigned to scan a large network range to find live hosts. The network is known for using strict TCP filtering rules on its firewall, which may obstruct common host…

Question

Options

• AUDP Ping Scan
• BlCMP ECHO Ping Scan
• CICMP Timestamp Ping Scan
• DTCP SYN Ping Scan

• A
  2% (1)
• B
  11% (6)
• C
  5% (3)
• D
  82% (45)

Explanation

TCP SYN Ping Scan Explanation

Why D is Correct: TCP SYN Ping Scan sends a SYN packet (the first step of the TCP three-way handshake) to a target port; if the host is alive, it responds with a SYN/ACK or RST, confirming its presence. This technique is highly effective at bypassing strict firewall rules because firewalls are often configured to allow SYN packets through on common ports (like 80 or 443), making it appear as legitimate traffic initiation.

Why the Distractors Are Wrong:

• A (UDP Ping Scan): UDP is unreliable for host discovery on filtered networks because firewalls frequently block UDP traffic, and hosts may not respond at all, making results inconsistent.
• B (ICMP ECHO Ping Scan): Standard ICMP Echo (ping) requests are among the first things blocked by strict firewalls, making this ineffective in filtered environments.
• C (ICMP Timestamp Ping Scan): While this is a slight variation of ICMP, it is still ICMP-based and is similarly blocked by firewalls that filter ICMP traffic broadly.

Memory Tip: Think "SYN = Sneak in" - a SYN packet mimics the start of a legitimate connection, allowing it to sneak past firewall rules that would block obvious probes like ICMP pings or UDP packets.

No community discussion yet for this question.