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

This scenario clearly indicates a SYN Flood attack, a classic Denial-of-Service technique discussed in CEH v13 Network and Perimeter Hacking. In a normal TCP three-way handshake, a client sends a SYN, the server responds with SYN-ACK, and the client completes the connection with an ACK. In a SYN flood, attackers send a massive number of SYN packets but never complete the handshake.

As described in CEH v13, the server allocates memory and resources for each half-open connection, placing them in the SYN_RECEIVED state. When these connections are not finalized, the server’s connection table becomes saturated, preventing legitimate users from establishing new sessions.

Other options are incorrect:

Smurf attacks rely on ICMP amplification, not TCP handshakes.

Ping of Death uses malformed ICMP packets.

UDP Floods overwhelm ports using UDP, not TCP session states.

CEH v13 emphasizes SYN floods as one of the most common Layer 4 DoS attacks due to their simplicity and effectiveness.

https://en.wikipedia.org/wiki/MAC_filtering

MAC filtering is a security method based on access control. Each address is assigned a 48-bit address, which is used to determine whether we can access a network or not. It helps in listing a set of allowed devices that you need on your Wi-Fi and the list of denied devices that you don’t want on your Wi-Fi. It helps in preventing unwanted access to the network. In a way, we can blacklist or white list certain computers based on their MAC address. We can configure the filter to allow connection only to those devices included in the white list. White lists provide greater security than blacklists because the router grants access only to selected devices.

It is used on enterprise wireless networks having multiple access points to prevent clients from communicating with each other. The access point can be configured only to allow clients to talk to the default gateway, but not other wireless clients. It increases the efficiency of access to a network.

The router allows configuring a list of allowed MAC addresses in its web interface, allowing you to choose which devices can connect to your network. The router has several functions designed to improve the network's security, but not all are useful. Media access control may seem advantageous, but there are certain flaws.

On a wireless network, the device with the proper credentials such as SSID and password can authenticate with the router and join the network, which gets an IP address and access to the internet and any shared resources.

MAC address filtering adds an extra layer of security that checks the device’s MAC address against a list of agreed addresses. If the client’s address matches one on the router’s list, access is granted; otherwise, it doesn’t join the network.

CEH v13 defines passive reconnaissance as information gathering without directly interacting with the target’s systems. Activities such as reviewing archived websites, social media, forums, and public records are all passive and legal.

Running an intensive port scan, however, is an active reconnaissance technique. According to CEH v13, port scanning directly interacts with target systems and can trigger IDS/IPS alerts, logs, and even legal consequences if done without authorization.

Therefore, option B violates the principles of passive reconnaissance and is the riskiest choice.

CEH v13 identifies automated patch management as the most secure and scalable approach. Automated tools ensure timely deployment, validation, rollback capability, and compliance reporting.

Manual patching increases human error. Applying patches from unknown sources introduces malware risk. Limiting patches contradicts best practices.

Therefore, Option B is correct.

A Network-based Intrusion Detection System (NIDS) monitors all network traffic for signs of suspicious activity across multiple hosts. In large environments with critical assets (e.g., financial or healthcare networks), NIDS is ideal because it provides visibility into entire network segments, not just individual systems.

NIDS can be deployed at strategic points (e.g., DMZs, VLANs, subnets) to detect unauthorized access, malware activity, or policy violations.

Reference – CEH v13 Official Courseware:

Module 13: Evading IDS, Firewalls, and Honeypots

Quote:

“Network-based IDS monitors traffic across an entire subnet or segment and is most effective in large environments to detect malicious activity before it reaches critical assets.”

Incorrect Options Explained:

A. Honeypots attract and log attacker behavior, but do not provide network-wide detection.

B. Firewalls filter traffic but are not detection systems.

D. HIDS monitors activity on a single host only.

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The Certified Ethical Hacker (CEH) Web Application Hacking and DoS/DDoS module identifies Slowloris as an application-layer denial-of-service attack that targets web servers by maintaining a large number of half-open HTTP connections.

Slowloris works by sending partial HTTP requests very slowly, preventing the server from closing the connections. CEH documentation highlights that this attack does not rely on high bandwidth, making it difficult to detect using traditional network-based defenses.

Option C accurately matches the described symptoms and CEH’s definition.

Options A and B are network-layer flooding attacks, which were explicitly ruled out.

Option D is a packet fragmentation attack, not an application-layer DoS technique.

CEH stresses tuning connection timeouts and using reverse proxies as mitigations.

A hybrid encryption system is a system that combines the advantages of both asymmetric and symmetric encryption algorithms. Asymmetric encryption, such as RSA, uses a pair of keys: a public key and a private key, which are mathematically related but not identical. Asymmetric encryption can provide key exchange, authentication, and non-repudiation, but it is slower and less efficient than symmetric encryption. Symmetric encryption, such as AES, uses a single key to encrypt and decrypt data. Symmetric encryption is faster and more efficient than asymmetric encryption, but it requires a secure way to share the key.

In a hybrid encryption system, RSA encryption is used for key exchange, and AES encryption is used for data encryption. This way, the system can benefit from the security of RSA and the speed of AES. However, the system also depends on the key sizes of both algorithms, which affect the security and performance of the system.

The key size of RSA encryption determines the number of bits in the public and private keys. The larger the key size, the more secure the encryption, but also the slower the key generation and encryption/decryption processes. The time complexity of generating an RSA key pair is O(n*2), where n is the key size in bits. This means that the time required to generate an RSA key pair increases quadratically with the key size. For example, if it takes 1 second to generate a 1024-bit RSA key pair, it will take 4 seconds to generate a 2048-bit RSA key pair, and 16 seconds to generate a 4096-bit RSA key pair.

The key size of AES encryption determines the number of bits in the symmetric key. The larger the key size, the more secure the encryption, but also the more rounds of encryption/decryption are needed. The time complexity of AES encryption is O(n), where n is the key size in bits. This means that the time required to encrypt/decrypt data increases linearly with the key size. For example, if it takes 1 second to encrypt/decrypt data with a 128-bit AES key, it will take 2 seconds to encrypt/decrypt data with a 256-bit AES key, and 4 seconds to encrypt/decrypt data with a 512-bit AES key.

An attacker has developed a quantum algorithm with time complexity O((log n)*2) to crack RSA encryption. This means that the time required to break RSA encryption decreases exponentially with the key size. For example, if it takes 1 second to break a 1024-bit RSA encryption, it will take 0.25 seconds to break a 2048-bit RSA encryption, and 0.0625 seconds to break a 4096-bit RSA encryption. This makes RSA encryption vulnerable to quantum attacks, unless the key size is very large.

Given n=4000 and variable AES key size, the scenario that is likely to provide the best balance of security and performance is C. AES key size=192 bits. This configuration is a compromise between options A and B, providing moderate security and performance. Option A, AES key size=128 bits, provides less security than option C, but RSA key generation and AES encryption will be faster. Option B, AES key size=256 bits, provides more security than option C, but RSA key generation may be slow. Option D, AES key size=512 bits, provides the highest level of security, but at a significant performance cost due to the large AES key size.

In CEH v13 Module 06: Malware Threats, code emulation is defined as a technique used by modern antivirus software where a virtual CPU and memory are created to safely execute and analyze malware in a sandboxed environment.

This allows the detection engine to observe runtime behavior of suspicious code without risking the actual system.

It’s more effective than signature-based detection for catching polymorphic and obfuscated malware.