What particular threat does FortiSandbox target?

FortiSandbox is specifically designed to address advanced threats by utilizing sandboxing technology to analyze unknown files. Sandboxing involves running files in a controlled environment to observe their behavior without risking an organization's operational environment. This is particularly crucial for detecting sophisticated malware that may not yet have signatures or known characteristics. By analyzing how these files behave once executed, FortiSandbox can identify malicious intent and provide organizations with the necessary insights to protect themselves from emerging threats. This proactive approach effectively counters advanced persistent threats and zero-day exploits, which are often designed to evade traditional security measures.

The other options, while significant in the realm of cybersecurity, do not specifically align with the primary function of FortiSandbox. Malicious insider threats and phishing attacks may require different types of detection and prevention strategies rather than the dynamic behavior analysis that sandboxing provides. Similarly, distributed denial of service attacks focus more on network availability rather than the file-based threats that FortiSandbox is engineered to analyze. Thus, the emphasis of FortiSandbox on resolving advanced threats through the sandboxing of unknown files clearly makes it the correct answer.