You receive an alert from FortiSandbox that a file has been rated 'highly malicious'. The FortiGate has the FortiSandbox inline scanning enabled with the action 'block malicious'. However, the file is still being downloaded by users. What is the most likely reason?
If the file type is excluded, FortiGate will not submit it to FortiSandbox for analysis, allowing it to pass.
Why this answer
FortiSandbox inline scanning only inspects file types that are explicitly listed in the scanning profile. If the file type (e.g., .zip, .pdf, or a specific executable extension) is not included in the profile, FortiGate will allow the file to pass through without sending it to FortiSandbox for analysis, even if the action is set to 'block malicious'. This explains why a file rated 'highly malicious' can still be downloaded by users.
Exam trap
The trap here is that candidates assume 'block malicious' applies universally to all files, but FortiSandbox inline scanning only inspects files whose types are explicitly configured in the scanning profile, so a missing file type bypasses the sandbox entirely.
How to eliminate wrong answers
Option A is wrong because if the FortiSandbox device were not reachable, FortiGate would typically fall back to a configured action (e.g., block or allow) or generate an alert, but the file would not be downloaded without some indication of the failure; the question states the file is still being downloaded, implying no connectivity issue was triggered. Option B is wrong because an IPS sensor blocking the connection before antivirus inspection would prevent the download entirely, not allow it to complete; the scenario describes the file being downloaded, so IPS is not the cause. Option C is wrong because an outdated antivirus database affects signature-based detection, but FortiSandbox inline scanning relies on cloud-based or sandbox analysis, not the local AV database; an outdated AV database would not prevent the file from being sent to FortiSandbox.