Pass the ECCouncil CEH v13 312-50v13 Questions and answers with ExamsMirror

A Denial of Service (DoS) attack is a type of cyberattack that aims to make a machine or network resource unavailable to its intended users by flooding it with traffic or requests that consume its resources. A TCP SYN flood attack is a type of DoS attack that exploits the TCP handshake process by sending a large number of SYN requests to the target server, without completing the connection. A UDP flood attack is a type of DoS attack that sends a large number of UDP packets to random ports on the target server, forcing it to check for the application listening at that port and reply with an ICMP packet. An ICMP flood attack is a type of DoS attack that sends a large number of ICMP packets, such as ping requests, to the target server, overwhelming its ICMP processing capacity.

The attacker’s strategy involves a unique mixture of TCP SYN, UDP, and ICMP floods, using ‘r’ packets per second. The server can handle ‘h’ packets per second before it starts showing signs of strain. If ‘r’ surpasses ‘h’, it overwhelms the server, causing it to become unresponsive. The attacker selects ‘r’ as a composite number and ‘h’ as a prime number, making the attack detection more challenging. This is because prime numbers are less predictable and more difficult to factorize than composite numbers, which may hinder the analysis of the attack pattern.

Considering ‘r=2010’ and different values for ‘h’, the scenario that would potentially cause the server to falter is the one where ‘h=1987’ (prime). This is because ‘r’ is greater than ‘h’ by 23 packets per second, which means the server cannot handle the incoming traffic and will eventually run out of resources. The other scenarios would not cause the server to falter, as ‘h’ is either greater than or very close to ‘r’, which means the server can either manage or barely cope with the incoming traffic. References:

What is a denial-of-service (DoS) attack? | Cloudflare

Denial-of-Service (DoS) Attack: Examples and Common Targets - Investopedia

DDoS Attack Types: Glossary of Terms

What is a Denial of Service (DoS) Attack? | Webopedia

According to CEH v13 Module 09: Social Engineering, Whaling is a specific type of phishing attack that targets senior executives and high-value individuals.

It’s called “whaling” because these individuals are the “big fish.”

Attacks are highly targeted and customized, often using knowledge of the executive’s company, responsibilities, or communication style.

The goal is to gain access to sensitive systems, financial assets, or confidential data.

Option Breakdown:

A. Spear phishing: Targeted phishing but not necessarily aimed at high-profile executives.

B. Whaling: Correct – phishing directed at C-level or VIP targets.

C. Vishing: Voice phishing – conducted over telephone/VoIP.

D. Phishing: General term – broader category.

Many network and system administrators don't pay enough attention to system clock accuracy and time synchronization. Computer clocks can run faster or slower over time, batteries and power sources die, or daylight-saving time changes are forgotten. Sure, there are many more pressing security issues to deal with, but not ensuring that the time on network devices is synchronized can cause problems. And these problems often only come to light after a security incident.

If you suspect a hacker is accessing your network, for example, you will want to analyze your log files to look for any suspicious activity. If your network's security devices do not have synchronized times, the timestamps' inaccuracy makes it impossible to correlate log files from different sources. Not only will you have difficulty in tracking events, but you will also find it difficult to use such evidence in court; you won't be able to illustrate a smooth progression of events as they occurred throughout your network.

A SYN flood attack is a type of denial-of-service (DoS) attack that exploits the TCP handshake process by sending a large number of SYN requests to the target server, without completing the connection. This consumes the connection state tables on the server, preventing it from accepting new connections. The attacker has crafted an automated botnet to simultaneously send ‘s’ SYN packets per second to the server. The server can handle ‘f’ SYN packets per second without any performance issues. If ‘s’ exceeds ‘f’, the network infrastructure begins to show signs of overload. The system’s response time increases exponentially (24k), where ‘k’ represents each additional SYN packet above the ‘f’ limit.

Considering ‘s=500’ and different ‘f’ values, the scenario that is most likely to cause the server to experience overload and significantly increased response times is the one where ‘f=420’. This is because ‘s’ is greater than ‘f’ by 80 packets per second, which means the server cannot handle the incoming traffic and will eventually run out of resources. The response time shoots up (2480 = 281,474,976,710,656 times the normal response time), indicating a system overload.

The other scenarios are less likely or less severe than the one where ‘f=420’. Option A has ‘f=510’, which is greater than ‘s’, so the system stays stable and the response time remains unaffected. Option B has ‘f=495’, which is less than ‘s’ by 5 packets per second, so the response time drastically rises (245 = 32 times the normal response time), indicating a probable system overload, but not as extreme as option D. Option C has ‘f=505’, which is less than ‘s’ by 5 packets per second, so the response time increases but not as drastically (245 = 32 times the normal response time), and the system might still function, albeit slowly. References:

SYN flood DDoS attack | Cloudflare

SYN flood - Wikipedia

What Is a SYN Flood Attack? | F5

What is a SYN flood attack and how to prevent it? | NETSCOUT

ARP Spoofing Attack ARP packets can be forged to send data to the attacker’s machine.Attackers flood a target computer’s ARP cache with forged entries, which is also known as poisoning. (P.1143/1127)

The most effective attack method for the penetration tester to exploit these vulnerabilities and attempt unauthorized access would be to execute a Brute Force attack, leveraging the lack of account lockout policy and the verbose error messages to guess the correct credentials. A Brute Force attack is a hacking method that uses trial and error to crack passwords, login credentials, or encryption keys. It is a simple yet reliable tactic for gaining unauthorized access to individual accounts and organizations’ systems and networks1. In this scenario, the tester can take advantage of the fact that the application does not lock out users after multiple failed login attempts, which means the tester can try as many combinations as possible without being blocked. The tester can also use the detailed error messages that disclose whether the username or password entered is incorrect, which can help narrow down the search space and reduce the number of guesses needed. For example, if the tester enters a wrong username and a wrong password, and the application responds with “Invalid username”, the tester can eliminate that username from the list of candidates and focus on finding the correct one. Similarly, if the tester enters a correct username and a wrong password, and the application responds with “Invalid password”, the tester can confirm that username and focus on finding the correct password. By using automated tools or scripts, the tester can perform a Brute Force attack faster and more efficiently.

The other options are not as effective or feasible as option A for the following reasons:

B. The tester could exploit a potential SQL Injection vulnerability to manipulate the application’s database: This option is not feasible because there is no indication that the application is vulnerable to SQL Injection, which is a web security vulnerability that allows an attacker to interfere with the queries that an application makes to its database2. The application uses form-based authentication, which does not necessarily involve SQL queries, and the error messages do not reveal any SQL syntax or structure. Moreover, even if the application was vulnerable to SQL Injection, the tester would need to craft a malicious SQL query that can bypass the authentication mechanism and grant access to the application, which may not be possible or easy depending on the database design and configuration.

C. The tester could launch a Cross-Site Scripting (XSS) attack to steal authenticated session cookies, potentially bypassing the clickjacking protection: This option is not effective because there is no evidence that the application is vulnerable to XSS, which is a web security vulnerability that allows an attacker to compromise the interactions that users have with a vulnerable application by injecting malicious scripts3. The application uses HTTP headers to prevent clickjacking attacks, which are a type of attack that tricks a user into clicking on a hidden or disguised element on a web page4. However, this does not imply that the application is vulnerable to XSS, which requires a different type of injection point and payload. Moreover, even if the application was vulnerable to XSS, the tester would need to find a way to deliver the malicious script to a legitimate user who is already authenticated, and then capture the stolen session cookies from the user’s browser, which may not be feasible or easy depending on the application’s design and security measures.

D. The tester could execute a Man-in-the-Middle (MitM) attack to intercept and modify the HTTP headers for a Clickjacking attack: This option is not feasible because a MitM attack is a type of attack that requires the attacker to insert themselves between two parties who believe that they are directly communicating with each other, and then relay or alter the communications between them5. In this scenario, the tester would need to intercept the HTTP traffic between the user and the application, and then modify the HTTP headers to remove or weaken the clickjacking protection. However, this would require the tester to have access to the network infrastructure or the user’s device, which may not be possible or easy depending on the network security and encryption. Moreover, even if the tester could perform a MitM attack, the tester would still need to trick the user into clicking on a malicious element on a web page, which may not be possible or easy depending on the user’s awareness and behavior.

Whitelist validation (also known as allowlist validation) is a robust defensive strategy where only pre-approved input formats are accepted. This includes:

Restricting input to specific data types (e.g., integer, string)

Limiting size, format, or allowed characters

Accepting only expected values (e.g., country codes, age ranges)

This practice is highly effective in mitigating SQL injection and other input-based attacks.

Incorrect Options:

A. Output encoding prevents XSS by encoding output but doesn't validate input.

B. Enforcing least privilege is an access control principle.

D. Blacklist validation is less secure and attempts to block known bad inputs, which may be bypassed.

Reference – CEH v13 Official Courseware:

Module 14: Hacking Web Applications

Section: “Input Validation and SQL Injection Mitigation”

Subsection: “Whitelist vs Blacklist Input Validation”

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https://ru.wikipedia.org/wiki/DNS_spoofing

DNS spoofing is a threat that copies the legitimate server destinations to divert the domain's traffic. Ignorant these attacks, the users are redirected to malicious websites, which results in insensitive and personal data being leaked. It is a method of attack where your DNS server is tricked into saving a fake DNS entry. This will make the DNS server recall a fake site for you, thereby posing a threat to vital information stored on your server or computer.

The cache poisoning codes are often found in URLs sent through spam emails. These emails are sent to prompt users to click on the URL, which infects their computer. When the computer is poisoned, it will divert you to a fake IP address that looks like a real thing. This way, the threats are injected into your systems as well.

Different Stages of Attack of DNS Cache Poisoning:

- The attacker proceeds to send DNS queries to the DNS resolver, which forwards the Root/TLD authoritative DNS server request and awaits an answer.

- The attacker overloads the DNS with poisoned responses that contain several IP addresses of the malicious website. To be accepted by the DNS resolver, the attacker's response should match a port number and the query ID field before the DNS response. Also, the attackers can force its response to increasing their chance of success.

- If you are a legitimate user who queries this DNS resolver, you will get a poisoned response from the cache, and you will be automatically redirected to the malicious website.

Zero Trust Networks The Zero Trust model is a security implementation that by default assumes every user trying to access the network is not a trusted entity and verifies every incoming connection before allowing access to the network.It strictly follows the principle, “Trust no one and validate before providing a cloud service or granting access permission.”It also allows companies to impose conditions, such as allowing employees to only access the appropriate resources required for their work role. (P.2997/2981)

Zero Trust is a strategic initiative that helps prevent successful data breaches by eliminating the concept of trust from an organization’s network architecture. Rooted in the principle of “never trust, always verify,” Zero Trust is designed to protect modern digital environments by leveraging network segmentation, preventing lateral movement, providing Layer 7 threat prevention, and simplifying granular user-access control.

“Clearing tracks” is a post-exploitation phase in the ethical hacking methodology in which the attacker removes or alters system evidence to hide their activities and avoid detection. This may include:

Deleting or modifying event logs

Clearing bash history or command history

Removing malware traces

Disabling auditing

From CEH v13:

Corrupting or erasing event logs ensures that system administrators or forensic investigators cannot trace the intrusion or determine how the system was compromised.

Incorrect Options:

A. Creating a backdoor is part of the "Maintaining Access" phase, not "Clearing Tracks."

B. Injecting a rootkit is part of the "Gaining or Maintaining Access" stage.

C. Exploiting a vulnerability is part of the "Gaining Access" phase.

Reference – CEH v13 Official Courseware:

Module 05: System Hacking

Section: “Clearing Logs and Erasing Evidence”

Subsection: “Track-Clearing Techniques”

Lab: Log Manipulation and Covering Tracks

In CEH v13 Module 12: Hacking Web Applications, Burp Suite is introduced as a powerful proxy-based tool used for intercepting, modifying, and analyzing HTTP/S traffic between a client and a web application.

Key Features of Burp Suite:

Captures all HTTP requests and responses.

Allows for manual testing of input parameters, headers, and cookies.

Includes tools such as Intruder, Repeater, Scanner, and Decoder.

Helps detect vulnerabilities such as XSS, SQLi, CSRF, and insecure session handling.

Option Review:

A. Maskgen: Used for generating masks, not a web proxy.

B. Dimitry: A footprinting tool, not used for request/response testing.

C. Burpsuite: Correct. Designed for web application vulnerability analysis.

D. Proxychains: Used to chain proxies for anonymity, not for HTTP traffic analysis.

https://www.cisco.com/c/en/us/support/docs/ip/access-lists/26448-ACLsamples.html

Since the first line prohibits any TCP traffic (access-list 102 deny tcp any any), the lines below will simply be ignored by the router. Below you will find the example from CISCO documentation.

This figure shows that FTP (TCP, port 21) and FTP data (port 20) traffic sourced from NetB destined to NetA is denied, while all other IP traffic is permitted.

FTP uses port 21 and port 20. TCP traffic destined to port 21 and port 20 is denied and everything else is explicitly permitted.

access-list 102 deny tcp any any eq ftp

access-list 102 deny tcp any any eq ftp-data

access-list 102 permit ip any any

In CEH v13 Module 01: Introduction to Ethical Hacking, Gray Hat hackers are described as those who operate between ethical and unethical lines:

Gray Hat Characteristics:

Discover vulnerabilities without permission.

May explore or exploit them without malicious intent, but also without authorization.

May or may not disclose them after exploration.

Not fully black hat (malicious), nor white hat (authorized and ethical).

In this case, John explored sensitive employee data without authorization, even though he worked for the organization. That behavior places him in the gray hat category.

Option Clarification:

A. Cybercriminal: Generally linked to criminal activities for gain.

B. Black hat: Unauthorized access with malicious or financial intent.

C. White hat: Authorized ethical hackers.

D. Gray hat: Correct – Unauthorized, curious access without immediate harm.

Web server footprinting is part of the reconnaissance phase in ethical hacking. It involves gathering detailed information about a web server’s structure, external links, available directories, scripts, and technologies in use.

Techniques include:

Spidering the site to map all accessible URLs and file paths

Identifying hidden directories or backup files

Analyzing page structures and URL patterns

This information helps attackers identify areas to target for further scanning or exploitation.

Incorrect Options:

A. Vulnerability scanning is active testing, not passive footprinting.

C. System-level data is gathered in OS or network footprinting.

D. Brute-force attacks are exploitation techniques, not reconnaissance.

Reference – CEH v13 Official Courseware:

Module 02: Footprinting and Reconnaissance

Section: “Web Server Footprinting Techniques”

Tool Reference: HTTrack, Burp Spider, OWASP ZAP

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Two-factor Authentication or 2FA is a user identity verification method, where two of the three possible authentication factors are combined to grant access to a website or application.1) something the user knows, 2) something the user has, or 3) something the user is.

The possible factors of authentication are:

· Something the User Knows:

This is often a password, passphrase, PIN, or secret question. To satisfy this authentication challenge, the user must provide information that matches the answers previously provided to the organization by that user, such as “Name the town in which you were born.”

· Something the User Has:

This involves entering a one-time password generated by a hardware authenticator. Users carry around an authentication device that will generate a one-time password on command. Users then authenticate by providing this code to the organization. Today, many organizations offer software authenticators that can be installed on the user’s mobile device.

· Something the User Is:

This third authentication factor requires the user to authenticate using biometric data. This can include fingerprint scans, facial scans, behavioral biometrics, and more.

For example: In internet security, the most used factors of authentication are:

something the user has (e.g., a bank card) and something the user knows (e.g., a PIN code). This is two-factor authentication. Two-factor authentication is also sometimes referred to as strong authentication, Two-Step Verification, or 2FA.

The key difference between Multi-Factor Authentication (MFA) and Two-Factor Authentication (2FA) is that, as the term implies, Two-Factor Authentication utilizes a combination of two out of three possible authentication factors. In contrast, Multi-Factor Authentication could utilize two or more of these authentication factors.