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

Simple Network Management Protocol (SNMP) enumeration involves querying devices on the network for information such as routing tables, interface statistics, and system details.

Useful tools include:

A. SNMPUtil: A command-line Microsoft utility for sending SNMP requests.

B. SNScan: Tool from Foundstone for SNMP scanning and enumeration.

C. SNMPScan: Lightweight tool for scanning networks for SNMP-enabled devices.

D. SolarWinds IP Network Browser: A commercial tool for graphical SNMP enumeration.

From CEH v13 Courseware:

Module 4: Enumeration

Subsection: SNMP Enumeration Tools

Incorrect Option:

E. NMap can detect SNMP services, but is not specialized for SNMP enumeration like the others.

Comprehensive and Detailed Explanation:

The code shown in the image is indicative of a Cross-Site Scripting (XSS) attack, where malicious JavaScript is injected into a web page via user input. In this case, the attacker includes:

%3Cscript%20src=...%3E — URL-encoded JavaScript tag to load a malicious script from an external source.

If the web application echoes this input back without sanitization, the script will execute in the context of the victim’s browser.

This allows the attacker to:

Steal cookies/session tokens

Perform actions on behalf of the victim

Redirect the victim to malicious websites

From CEH v13 Courseware:

Module 10: Web Application Hacking → Cross-Site Scripting (XSS)

The nbtstat command is a Windows utility that displays NetBIOS over TCP/IP (NetBT) protocol statistics, NetBIOS name tables, and the NetBIOS name cache. However, the nbtstat command does not support IPv6 addresses, which are the standard format for the Internet Protocol version 6 (IPv6). Therefore, using the nbtstat command with IPv6 addresses will result in an error message or no output. To enumerate NetBIOS names on a network that uses IPv6, you should switch to an enumeration tool that supports IPv6, such as Nmap, which is a network scanning and security auditing tool. Nmap has a scripting engine (NSE) that allows users to write and execute scripts for various network tasks, including NetBIOS enumeration. Nmap can also detect the operating system, services, and vulnerabilities of the target machines, regardless of the IP version they use. References:

Nbtstat Command - Computer Hope

Nbtstat CMD: Windows Network Command Line Prompt

[Nmap Scripting Engine (NSE) Documentation]

flags –source-port and -g are equivalent and instruct nmap to send packets through a selected port. this option is used to try to cheat firewalls whitelisting traffic from specific ports. the following example can scan the target from the port twenty to ports eighty, 22, 21,23 and 25 sending fragmented packets to LinuxHint.

1. AV (Asset value) = $300 + (14 * $10) = $440 - the cost of a hard drive plus the work of a recovery person, i.e.how much would it take to replace 1 asset? 10 hours for resorting the OS and soft + 4 hours for DB restore multiplies by hourly rate of the recovery person.

2. SLE (Single Loss Expectancy) = AV * EF (Exposure Factor) = $440 * 1 = $440

3. ARO (Annual rate of occurrence) = 1/3 (every three years, meaning the probability of occurring during 1 years is 1/3)

4. ALE (Annual Loss Expectancy) = SLE * ARO = 0.33 * $440 = $145.2

Most likely have an issue with DNS.

DNS stands for “Domain Name System.” It’s a system that lets you connect to websites by matching human-readable domain names (like example.com) with the server's unique ID where a website is stored.

Think of the DNS system as the internet’s phonebook. It lists domain names with their corresponding identifiers called IP addresses, instead of listing people’s names with their phone numbers. When a user enters a domain name like wpbeginner.com on their device, it looks up the IP address and connects them to the physical location where that website is stored.

NOTE: Often DNS lookup information will be cached locally inside the querying computer or remotely in the DNS infrastructure. There are typically 8 steps in a DNS lookup. When DNS information is cached, steps are skipped from the DNS lookup process, making it quicker. The example below outlines all 8 steps when nothing is cached.

The 8 steps in a DNS lookup:

1. A user types ‘example.com’ into a web browser, and the query travels into the Internet and is received by a DNS recursive resolver;

2. The resolver then queries a DNS root nameserver;

3. The root server then responds to the resolver with the address of a Top-Level Domain (TLD) DNS server (such as .com or .net), which stores the information for its domains. When searching for example.com, our request is pointed toward the .com TLD;

4. The resolver then requests the .com TLD;

5. The TLD server then responds with the IP address of the domain’s nameserver, example.com;

6. Lastly, the recursive resolver sends a query to the domain’s nameserver;

7. The IP address for example.com is then returned to the resolver from the nameserver;

8. The DNS resolver then responds to the web browser with the IP address of the domain requested initially;

Once the 8 steps of the DNS lookup have returned the IP address for example.com, the browser can request the web page:

9. The browser makes an HTTP request to the IP address;

10. The server at that IP returns the webpage to be rendered in the browser.

NOTE 2: DNS primarily uses the User Datagram Protocol (UDP) on port number 53 to serve requests. And if this port is blocked, then a problem arises already in the first step. But the ninth step is performed without problems.

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.

https://en.wikipedia.org/wiki/Salt_(cryptography)

A salt is random data that is used as an additional input to a one-way function that hashes data, a password, or passphrase. Salts are used to safeguard passwords in storage. Historically a password was stored in plaintext on a system, but over time additional safeguards were developed to protect a user's password against being read from the system. A salt is one of those methods.

A new salt is randomly generated for each password. In a typical setting, the salt and the password (or its version after key stretching) are concatenated and processed with a cryptographic hash function, and the output hash value (but not the original password) is stored with the salt in a database. Hashing allows for later authentication without keeping and therefore risking exposure of the plaintext password in the event that the authentication data store is compromised.

Salts defend against a pre-computed hash attack, e.g. rainbow tables. Since salts do not have to be memorized by humans they can make the size of the hash table required for a successful attack prohibitively large without placing a burden on the users. Since salts are different in each case, they also protect commonly used passwords, or those users who use the same password on several sites, by making all salted hash instances for the same password different from each other.