312-50v12 Exam Dumps - Certified Ethical Hacker Exam (CEHv12)

· Identifying operating systems, services, protocols and devices,

· Collecting unencrypted information about usernames and passwords,

· Capturing network traffic for further analysis

are passive network sniffing methods since with the help of them we only receive information and do not make any changes to the target network. When modifying and replaying the captured network traffic, we are already starting to make changes and actively interact with it.

The action that would best protect your web server from potential misconfiguration-based attacks is performing regular server configuration audits. A server configuration audit is a process of reviewing and verifying the security settings and parameters of the server, such as user accounts, permissions, services, ports, protocols, files, directories, logs, and patches. A server configuration audit can help you to identify and fix any security misconfigurations that may expose your server to attacks, such as using default credentials, enabling unnecessary services, leaving open ports, or missing security updates. A server configuration audit can also help you to comply with the security standards and best practices for your server, such as the CIS Benchmarks or the OWASP Secure Configuration Guide12.

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

• B. Enabling multi-factor authentication for users: This option is not relevant because it does not address the server misconfiguration issue, but the user authentication issue. Multi-factor authentication is a method of verifying the identity of the users by requiring them to provide two or more pieces of evidence, such as a password, a code, or a biometric factor. Multi-factor authentication can enhance the security of the user accounts and prevent unauthorized access, but it does not prevent the server from being attacked due to misconfigured settings or parameters3.
• C. Implementing a firewall to filter traffic: This option is not sufficient because it does not prevent the server from being misconfigured, but only limits the exposure of the server to the network. A firewall is a device or software that monitors and controls the incoming and outgoing network traffic based on predefined rules. A firewall can protect the server from external attacks by blocking or allowing certain ports, protocols, or IP addresses. However, a firewall cannot protect the server from internal attacks or from attacks that exploit the allowed traffic. Moreover, a firewall itself can be misconfigured and cause security issues4.
• D. Regularly backing up server data: This option is not preventive but reactive, as it does not protect the server from being attacked, but only helps to recover the data in case of an attack. Backing up server data is a process of creating and storing copies of the data on the server, such as files, databases, or configurations. Backing up server data can help you to restore the data in case of data loss, corruption, or deletion due to an attack. However, backing up server data does not prevent the server from being attacked in the first place, and it does not fix the security misconfigurations that may have caused the attack5.

References:

• 1: Server Configuration Audit - an overview | ScienceDirect Topics
• 2: Secure Configuration Guide - OWASP Foundation
• 3: Multi-factor authentication - Wikipedia
• 4: Firewall (computing) - Wikipedia
• 5: Backup - Wikipedia

SQL Injection is a type of attack that exploits a vulnerability in a web application that uses a SQL database. The attacker injects malicious SQL code into the user input, such as a login form, that is then executed by the database server. This can allow the attacker to access, modify, or delete data, or execute commands on the database server.

The ‘UNION’ SQL keyword is often used in SQL Injection attacks to combine the results of two or more SELECT statements into a single result set. This can allow the attacker to retrieve additional data from other tables or columns that are not intended to be displayed by the application. For example, if the application uses the following query to check the user credentials:

SELECT * FROM users WHERE username = '$username' AND password = '$password'

The attacker can inject a ‘UNION’ statement to append another query, such as:

' OR 1 = 1 UNION SELECT * FROM credit_cards --

This will result in the following query being executed by the database server:

SELECT * FROM users WHERE username = '' OR 1 = 1 UNION SELECT * FROM credit_cards --' AND password = '$password'

The first part of the query will always return true, and the second part of the query will return the data from the credit_cards table. The ‘–’ symbol is a comment that will ignore the rest of the query. The attacker can then see the credit card information in the application’s response.

However, some web applications implement security measures to prevent SQL Injection attacks, such as filtering special characters in user inputs. Special characters are symbols that have a special meaning in SQL, such as quotes, semicolons, dashes, etc. By filtering or escaping these characters, the application can prevent the attacker from injecting malicious SQL code. For example, if the application replaces single quotes with two single quotes, the previous injection attempt will fail, as the query will become:

SELECT * FROM users WHERE username = '''' OR 1 = 1 UNION SELECT * FROM credit_cards --'' AND password = '$password'

This will result in a syntax error, as the query is not valid SQL.

In this challenging environment, if the hacker still intends to exploit this SQL Injection vulnerability, the strategy that he is most likely to employ is to bypass the special character filter by encoding his malicious input. Encoding is a process of transforming data into a different format, such as hexadecimal, base64, URL, etc. By encoding his input, the hacker can avoid the filter and still inject malicious SQL code. For example, if the hacker encodes his input using URL encoding, the previous injection attempt will become:

%27%20OR%201%20%3D%201%20UNION%20SELECT%20*%20FROM%20credit_cards%20--

This will result in the following query being executed by the database server, after the application decodes the input:

SELECT * FROM users WHERE username = '' OR 1 = 1 UNION SELECT * FROM credit_cards --' AND password = '$password'

This will succeed in returning the credit card information, as the filter will not detect the special characters in the encoded input.

Therefore, the hacker is most likely to employ the strategy of bypassing the special character filter by encoding his malicious input, which could potentially enable him to successfully inject damaging SQL queries.

References:

• SQL Injection | OWASP Foundation
• SQL Injection Union Attacks
• SQL Injection Bypassing WAF

https://linuxsecurityblog.com/2018/12/23/create-a-backdoor-with-cryptcat/

Cryptcat enables us to communicate between two systems and encrypts the communication between them with twofish, one of many excellent encryption algorithms from Bruce Schneier et al. Twofish’s encryption is on par with AES encryption, making it nearly bulletproof. In this way, the IDS can’t detect the malicious behavior taking place even when its traveling across normal HTTP ports like 80 and 443.

Objectives of Footprinting Draw Network Map - Combining footprinting techniques with tools such as Tracert allows the attacker to create diagrammatic representations of the target organization’s network presence. Specficially, it allows attackers to draw a map or outline of the target organization’s network infrastructure to know about the actual environment that they are going to break into. These network diagrams can guide the attacker in performing an attack. (P.114/98)