CEH Practice Test 4 — 10 Questions

Question 1

An organization experiences a DDoS attack where the attacker sends a flood of UDP packets to a server, causing it to become unresponsive. The packets appear to come from many different source IP addresses and are directed to random high-numbered ports. Which type of DDoS attack is this?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

UDP flood. A UDP flood attack works by overwhelming a target server with a high volume of UDP packets sent to random high-numbered ports. The server checks each port for a listening application, and when none is found, it responds with ICMP Destination Unreachable messages, consuming CPU and bandwidth until the server becomes unresponsive. The use of spoofed source IP addresses makes it difficult to filter the attack traffic based on source alone.

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ICMP flood

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SYN flood

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Smurf attack

Question 2

Refer to the exhibit. A security analyst notices multiple ESTABLISHED connections on port 443 from different external IPs to the same process ID. What type of attack is most likely occurring?

Accepted Answer

Distributed denial-of-service (DDoS) attack. Multiple ESTABLISHED connections on port 443 (HTTPS) from different external IPs to the same process ID indicate a distributed denial-of-service (DDoS) attack. In a DDoS, many compromised hosts (botnet) simultaneously establish legitimate TCP handshakes and maintain connections to exhaust server resources, such as connection slots or memory, at the application layer. The key clue is the diversity of source IPs targeting a single process, which is characteristic of a coordinated flood from many distinct sources.

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SSL/TLS renegotiation DoS

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Slowloris attack

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Man-in-the-middle attack

Question 3

A penetration tester runs the following Nmap command: nmap -sS -sV -O -p 22,80,443,3389 192.168.1.0/24. Which of the following BEST describes what this scan will accomplish?

Accepted Answer

Perform a TCP SYN scan on four ports, detect service versions, and attempt OS fingerprinting. The `-sS` flag initiates a TCP SYN stealth scan, `-sV` enables service version detection on open ports, and `-O` attempts OS fingerprinting. The scan is limited to ports 22, 80, 443, and 3389 across the 192.168.1.0/24 subnet. This combination performs a half-open scan on those four ports, identifies the versions of services running on them, and tries to determine the operating system of each host.

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Perform a full TCP connect scan with UDP service detection on all ports

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Perform an aggressive scan of all open ports and enumerate SMB shares

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Perform a UDP scan on the four specified ports and identify running services

Question 4

During a penetration test, a tester uses Nmap with the command: nmap -sS -D RND:10 192.168.1.100. After the scan, the IDS logs show multiple SYN packets from different source IPs hitting the target. However, the tester's true IP is not among them. Which of the following techniques is being used?

Accepted Answer

Decoy scan. The command `nmap -sS -D RND:10` performs a SYN stealth scan with 10 randomly generated decoy IP addresses. The IDS logs show multiple SYN packets from different source IPs, but the tester's true IP is not among them because Nmap sends the decoy packets with spoofed source addresses while the real scan packet is interleaved among them. This is the definition of a decoy scan, which aims to obscure the attacker's true origin by blending it with fake sources.

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Idle scan

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SYN flood

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Fragmentation attack

Question 5

Which of the following tools is specifically designed to perform password cracking using rainbow tables?

Accepted Answer

RainbowCrack. RainbowCrack is specifically designed to perform password cracking using precomputed rainbow tables, which are time-memory trade-off structures that allow hashes to be reversed quickly without brute-forcing each password. Unlike other tools that rely on brute force, dictionary attacks, or hybrid methods, RainbowCrack's core functionality is built around generating and using rainbow tables to crack LM, NTLM, MD5, SHA1, and other hash types.

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John the Ripper

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Ophcrack

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Hashcat

Question 6

Which tool is specifically designed to crack Windows LM and NTLM password hashes using rainbow tables?

Accepted Answer

Ophcrack. Ophcrack is specifically designed to crack Windows LM and NTLM password hashes using precomputed rainbow tables. It leverages the time-memory trade-off technique to rapidly reverse these hashes without brute-forcing each password individually, making it the correct choice for this targeted task.

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Hashcat

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RainbowCrack

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John the Ripper

Question 7

During a ransomware incident response, a forensic analyst recovers a suspicious file that appears to be a PE executable. The analyst wants to quickly check if the file is known malware without executing it. Which of the following is the BEST first step?

Accepted Answer

Submit the file hash to VirusTotal. Submitting the file hash to VirusTotal is the best first step because it leverages aggregated antivirus engines and threat intelligence to quickly determine if the file is known malware, without any execution risk. This approach is fast, non-invasive, and provides immediate reputation data from over 70 security vendors, making it ideal for triage during incident response.

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Disassemble the file using IDA Pro

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Perform static analysis using PEiD to identify compiler and packer

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Run the file in a sandbox and observe its behavior

Question 8

A security analyst wants to identify all live hosts on a network without generating excessive traffic. Which of the following techniques is MOST appropriate for this purpose?

Accepted Answer

Ping sweep using ICMP echo requests. A ping sweep using ICMP Echo Requests (Type 8) is the most efficient method to identify live hosts on a network because it sends a single packet per target and listens for ICMP Echo Replies (Type 0). This generates minimal traffic compared to full port scans, making it ideal for initial reconnaissance without overwhelming the network or triggering intrusion detection systems.

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Banner grabbing with Netcat

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Full TCP connect scan on all ports

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UDP scan on common ports

Question 9

A user receives a phone call from someone claiming to be from IT support, asking for their password to perform a system update. This is an example of which social engineering technique?

Accepted Answer

Pretexting. Pretexting is a social engineering technique where an attacker fabricates a scenario (pretext) to manipulate a target into divulging sensitive information. In this case, the caller creates a false identity (IT support) and a false reason (system update) to trick the user into revealing their password. This differs from other techniques because it relies on a constructed narrative rather than malicious software or direct impersonation via email or phone alone.

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Baiting

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Phishing

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Vishing

Question 10

An attacker uses a tool that precomputes hash chains for common passwords to crack password hashes quickly. Which technique is the attacker employing?

Accepted Answer

Rainbow table attack. Rainbow table attack. This technique involves precomputing hash chains for common passwords and storing them in a table, allowing the attacker to reverse password hashes quickly by looking up the hash in the table rather than computing hashes on the fly. The tool described matches the core concept of a rainbow table, which uses a time-memory trade-off to crack hashes efficiently.

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Dictionary attack

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Brute-force attack

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Hybrid attack