312-50v13 Exam Dumps - Certified Ethical Hacker Exam (CEHv13)

The correct answer is A because AXFR is the DNS operation used for a full zone transfer. In DNS, a zone transfer copies DNS zone data from one DNS server to another, usually from a primary authoritative server to a secondary server for replication and redundancy. CEH DNS enumeration topics emphasize that zone transfers are valuable during reconnaissance because they can reveal DNS records, hostnames, mail servers, name servers, IP addresses, and other infrastructure details. The referenced CEH material identifies zone transfer as a DNS transfer where all SOA records are transmitted to the requester and states that the full zone transfer option uses opcode AXFR, while incremental transfer uses IXFR. It also shows the practical command pattern dig < domain.com > axfr for requesting a zone transfer. AXFR is not encryption, DNS tunneling, or normal DNS resolution; it specifically allows full DNS zone transfer.

In OT hacking methodology, once exposed industrial assets have been identified, the next logical step—before attempting exploitation—is to actively assess those assets for weaknesses. The scenario states the tester is “actively probing controllers, services, and interfaces to identify exploitable weaknesses” and explicitly confirms that no exploitation attempts or persistence mechanisms have occurred. That combination maps most closely to the Vulnerability Scanning phase.

Vulnerability scanning in OT contexts includes carefully enumerating and assessing industrial components such as PLCs, HMIs, historians, engineering workstations, and industrial gateways. The goal is to discover issues like outdated firmware, insecure services, weak authentication, exposed management interfaces, misconfigurations, and known CVEs affecting industrial protocols or device web consoles. “Actively probing” is an important clue: information gathering can be passive (asset inventories, diagrams, OSINT, passive network visibility), but scanning moves into active interaction with hosts and services to identify vulnerabilities—still short of exploitation.

The other answer choices do not align with the described boundaries. Gain Remote Access implies initial compromise or establishing access paths (e.g., leveraging credentials, remote services, or exploits) and is a later step once weaknesses are identified and selected. Launch Attacks is even further along, where exploitation or disruption actions occur. Information Gathering would fit earlier when the tester is identifying assets and collecting details with minimal interaction; however, the scenario says that stage is already past (“has already identified exposed industrial assets”) and that the tester is now probing for exploitable weaknesses.

Therefore, the current phase is D. Vulnerability Scanning.

The CEH Cryptanalysis module describes differential cryptanalysis as an attack that studies the relationship between differences in input and resulting differences in output to recover secret keys.

Option A precisely matches this definition.

Option B relies on execution timing.

Option C requires ciphertext manipulation.

Option D exhaustively tests keys.

CEH lists differential cryptanalysis as a foundational theoretical attack.

In CEH v13, IDS effectiveness is closely tied to proper signature tuning and sensitivity thresholds. When IDS alerts are triggered by legitimate user behavior, the most common cause is overly sensitive configuration, resulting in false positives.

False positives occur when normal traffic patterns match intrusion signatures. CEH v13 emphasizes that IDS systems must be calibrated to the organization’s baseline traffic profile. Without tuning, IDS logs become noisy and reduce analyst effectiveness.

Firewall issues (Option A) and outdated IDS signatures (Option B) can cause missed detections, not excessive alerts. Users unintentionally triggering protocols (Option D) is not a root cause but a symptom of misconfiguration.

Thus, excessive IDS sensitivity is the correct explanation.

This scenario describes a Slowloris attack, a classic application-layer DoS attack covered in CEH v13 Network and Perimeter Hacking. Slowloris works by opening many HTTP connections and sending data very slowly, preventing the server from closing the connections.

Because the connections appear legitimate, the server keeps them open, eventually exhausting its connection pool. This causes legitimate users to experience timeouts and service unavailability—exactly as described.

ICMP and UDP floods consume bandwidth, which was ruled out. Fragmentation attacks target packet handling, not application-layer sessions.

CEH v13 highlights Slowloris as particularly dangerous because it requires minimal bandwidth and bypasses many traditional DoS defenses. Therefore, Option A is correct.

A NULL scan is a TCP port scanning technique in which the attacker sends a TCP packet with no flags set. This technique is commonly used during the network reconnaissance and port-scanning phase to identify open and closed ports while attempting to evade some security controls and logging mechanisms.

According to TCP/IP behavior defined in RFC 793 and discussed in CEH network scanning concepts, when a NULL packet is sent to a closed port, the target system should respond with a TCP RST (Reset) packet. The RST packet indicates that no service is listening on that port and that the connection attempt should be terminated immediately.

When the port is open, most UNIX/Linux systems generally do not respond to a NULL scan packet. Therefore, scanners such as Nmap interpret no response as either an open or filtered port and RST as a closed port.

Option A (No response) is associated with an open port in a typical NULL scan, not a closed one. Options B, D, E, and F are incorrect because FIN, SYN, ACK, and PSH are not the expected responses from a closed port during a NULL scan.

CEH cloud modules explain that side-channel attacks exploit indirect information leakage based on hardware characteristics—such as CPU timing, power usage, cache access patterns, or electromagnetic emissions. In virtualized cloud environments, multiple tenants share the same physical hardware, creating opportunities for attackers to extract sensitive data from neighboring virtual machines. By placing a malicious VM on the same host as the victim, an attacker can measure minute differences in timing during cryptographic operations, allowing them to infer private keys or sensitive computations. This aligns precisely with CEH’s definition of a side-channel attack. Cryptojacking involves unauthorized cryptocurrency mining, CPDoS targets caching layers rather than key extraction, and metadata spoofing manipulates cloud metadata endpoints. Only side-channel analysis matches the described attack behavior.

This scenario illustrates physical impersonation, a social engineering tactic discussed in CEH v13 Social Engineering. The attacker exploits trust in appearance and role assumption, dressing as a network technician to gain access without challenge.

Unlike tailgating (which involves following someone), this attack relies on assumed authority and familiarity. CEH v13 categorizes this under impersonation attacks, where attackers pose as employees, contractors, or vendors.

Other options describe different social engineering vectors:

A: Phone-based pretexting

B: Dumpster diving

C: Vishing

Physical impersonation is particularly dangerous because it bypasses technical controls entirely. Option D best matches the scenario.