Cisco Updated 300-215 Exam Questions and Answers by arley

Comprehensive and Detailed Explanation:

The log entries show repeated SSH login attempts for various invalid usernames (e.g., admin, phoenix, rainbow, test, user, etc.) from different source ports. These are clear signs of a brute-force attack—an automated process trying multiple usernames and passwords in hopes of gaining access.

Mitigating such attacks includes:

Implementing account lockout policies (e.g., locking an account after several failed login attempts).

Enabling Multi-Factor Authentication (MFA) to ensure that password guessing alone is insufficient for account access.

Therefore, the correct answer is:

D. Brute-force attack; implement account lockout policies and roll out MFA.

Input validation (A) is a critical countermeasure to defend against command injection and related vulnerabilities, as discussed in the Cisco guide. Proper validation ensures that malicious commands or payloads are not accepted or executed by the web application.

File integrity monitoring (E) helps detect unauthorized changes such as log deletion or binary modification, making it a crucial tool in recognizing and investigating tampering attempts.Blocking port 443 (B) would disable HTTPS and is not a practical solution. Antivirus (C) does not prevent form-based application attacks, and merely updating the application (D) may not be sufficient without addressing the underlying input validation flaw.

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YARA rulesare designed to identifyfilesthat match specific patterns, strings, or binary characteristics.

The Cisco CyberOps guide states:

“YARA helps researchers and analysts identify and classify malware samples based on textual or binary patterns”.

When Web Application Firewalls (WAFs) are configured to block specific patterns (like${), attackers may bypass this using URL encoding (e.g.,%24%7B). In such cases, the WAF must decode these patterns before applying matching rules. EnablingURL decodingensures the WAF recognizes encoded payloads and applies protections appropriately. This is a recommended hardening strategy against bypass techniques for command injection and remote code execution.