A security analyst is reviewing logs and discovers the following: Which of the following should be used to best mitigate this type of attack?

Input sanitization is the best mitigation because it directly addresses the vulnerability shown in the logs. The log entry UNION SELECT NULL, NULL, @@version indicates a SQL injection attempt, where an attacker is trying to manipulate database queries by injecting malicious SQL code. Input sanitization involves validating, filtering, and cleaning user input to prevent such malicious code from being executed by the application's backend. Secure cookies primarily protect session integrity and confidentiality, not against SQL injection. Static code analysis helps identify vulnerabilities in source code before deployment but doesn't prevent attacks on a live system. Sandboxing isolates processes to limit damage from exploits but doesn't prevent the initial injection attempt itself.