Ethical hacking is performed with proper authorization to identify vulnerabilities and improve a system's security. It is a controlled and legal practice that helps organizations to defend against malicious attacks.

A firewall serves as a barrier between a trusted internal network and untrusted external networks. It filters incoming and outgoing traffic based on predetermined security rules, allowing only safe communications.

Phishing is a social engineering technique where attackers send deceptive messages to trick users into divulging personal or financial information. Recognizing phishing attempts is essential for maintaining cybersecurity.

A strong password should mix letters, numbers, and symbols to be less predictable. '5tr0ng#Pa$$!' uses multiple character types, making it more secure against common cracking techniques.

Encryption protocols such as SSL/TLS encrypt data during transmission, protecting it from interception and tampering. This is a fundamental security measure for ensuring privacy on the internet.

Multi-factor authentication adds additional layers of security by requiring multiple proofs of identity. By utilizing factors such as something you know and something you have, it significantly reduces the risk of unauthorized access.

Symmetric encryption relies on one key for both encrypting and decrypting the data, making it efficient for large data volumes. However, the challenge lies in securely sharing the key between parties.

SQL injection occurs when user inputs are not properly sanitized, allowing execution of malicious SQL commands. This vulnerability can lead to unauthorized access to or manipulation of the database.

Dynamic memory allocation with bounds checking ensures that data does not exceed the allocated buffer limits, thereby helping to prevent buffer overflow attacks. This feature is crucial in maintaining program stability and security.

Worms are self-replicating malware that can autonomously propagate through networks, while viruses typically need to be attached to a host file and require user action to spread. This distinction is important for developing targeted security defenses.

A zero-day exploit leverages a vulnerability that is not yet known to the vendor and has not been patched. This makes it particularly dangerous since defenses are not yet in place.

Using default passwords significantly compromises security because they are widely known and easily exploitable. Best practices include regular software updates, strong password policies, and encryption to protect sensitive information.

A DoS attack floods a system with excessive traffic, which exhausts its resources and prevents it from handling legitimate requests. This leads to service unavailability and disruption of normal operations.

Automatically escaping user input prevents execution of malicious scripts by converting special characters into a safe format. This is an effective way to mitigate XSS vulnerabilities in web applications.

The principle of least privilege means that both users and programs should have only the minimum level of access required to perform their functions. This limits potential damage from security breaches by reducing unnecessary access rights.

The function converts the string '5' to an integer successfully and then multiplies it by 2, resulting in 10. The try-except block is designed to catch errors, but in this case, no error occurs.

A man-in-the-middle attack involves an attacker secretly intercepting and possibly modifying the communication between two parties. This can lead to unauthorized data access, manipulation, or impersonation of one of the communicating parties.

Implementing a Content Security Policy (CSP) restricts the sources from which web content can be loaded, thereby reducing the risk of executing malicious scripts. This measure is effective in mitigating injection attacks such as XSS.

Secure error handling involves displaying a generic message to the user while logging detailed error information securely. This prevents sensitive system details from being exposed to potential attackers.

Enforcing strong password policies makes passwords harder to guess, thereby increasing resistance to brute-force attacks. Complex passwords result in a larger search space, meaning attackers must try many more combinations.