312-50v13 Exam Questions Tutorials

Spear-phishing is a targeted form of phishing that uses personalized and context-rich information to increase credibility. CEH emphasizes that referencing specific internal projects, financial data, or organizational events significantly raises the success rate when attacking high-value targets such as executives. This tailored approach avoids suspicion and exploits trust more effectively than broad or generic phishing attempts.

A FIN scan is a classic “stealth” TCP scan technique discussed in CEH network scanning methodology. Unlike a TCP Connect scan, which completes the full three-way handshake and is highly visible in logs, a FIN scan sends a TCP packet with only the FIN flag set to a target port. The scan then interprets the target’s response to infer whether the port is open or closed, without establishing a normal TCP session. This matches the scenario’s requirement to “infer port states without completing a full connection” and to keep visibility low.

The logic relies on expected TCP behavior defined for many TCP/IP stacks. For a closed port, the target typically responds with an RST packet, indicating there is no service listening. For an open port, many systems do not respond at all to an unexpected FIN packet (because it does not correspond to an existing connection). That “no response” behavior becomes the signal the tester uses to suspect the port may be open or filtered. CEH emphasizes that because FIN scans do not perform a handshake, they can be less likely to trigger certain basic connection-based logging, and they generate fewer obvious connection events than TCP Connect scans.

Option D, NULL scan, is also a stealth method, but it uses a packet with no flags set. The question specifically highlights leveraging TCP flags and is commonly mapped in CEH-style questions to FIN scanning as the representative “TCP flag stealth scan.” Option B is too generic, and option A is the most detectable. Therefore, FIN scan best aligns with the described stealth reconnaissance strategy.

CEH v13 explains that Side-Channel Attacks exploit physical characteristics of cryptographic devices—such as power consumption, timing variations, electromagnetic leakage, or acoustic emissions—to infer confidential data like encryption keys. These attacks do not break the cryptographic algorithm itself but instead analyze unintended signals produced during computation. The scenario describes a classic power analysis and timing analysis attack, where the attacker monitors fluctuations during encryption operations on a smart card. CEH details how Differential Power Analysis (DPA) and Simple Power Analysis (SPA) allow attackers to extract secret keys by statistically correlating measured power traces to cryptographic operations. This type of attack is extremely dangerous because it bypasses mathematical strength and targets hardware implementation flaws. Options A, C, and D do not relate to side-channel exploitation. CEH specifically categorizes this method as observing hardware emissions to deduce secrets, making Option B the most accurate match.

According to CEH v13, one of the most effective defenses against rogue DHCP servers is DHCP snooping, a Layer 2 security feature that classifies switch ports as either trusted or untrusted. DHCP responses are permitted only on trusted ports, typically those connected to legitimate DHCP servers. Any DHCP OFFER or ACK originating from an untrusted port is dropped automatically. In the scenario, the rogue DHCP server is sending unauthorized configuration settings because the switch is forwarding DHCP messages from all ports without restriction. CEH specifically warns that unmanaged or misconfigured switches allow rogue DHCP servers to assign malicious DNS, gateway, or IP configurations, enabling traffic redirection, interception, or man-in-the-middle attacks. ARP inspection (Option B) protects against ARP spoofing but not DHCP abuses. Port security (Option C) prevents MAC flooding, not DHCP impersonation. Static reservations (Option D) do not scale and do not stop rogue DHCP servers. DHCP snooping directly mitigates this threat.