Inspection mode differences for antivirus
This section identifies the behavioral differences between Antivirus operating in flow and proxy inspection.
Feature comparison between antivirus inspection modes
The following table indicates which Antivirus features are supported by their designated scan modes.
| Part1 | Replacement Message | Content Disarm | Mobile Malware | Virus Outbreak | Sandbox Inspection | NAC Quarantine |
|---|---|---|---|---|---|---|
| Proxy | Yes | Yes | Yes | Yes | Yes | Yes |
| Flow default Mode | Yes* | No | No | No | Yes | Yes |
| Flow legacy Mode | Yes* | No | Yes | Yes | Yes | Yes |
*IPS Engine caches the URL and a replacement message will be presented after the second attempt.
| Part 2 | Archive Blocking | Emulator | Client Comforting | Infection Quarantine | Heuristics | Treat EXE as Virus |
|---|---|---|---|---|---|---|
| Proxy | Yes | Yes | Yes | Yes (1) | Yes | Yes (2) |
| Flow default Mode | No | No | No | No | No | No |
| Flow legacy Mode | Yes | Yes | No | Yes (1) | Yes | Yes (2) |
- Only available on FortiGate models with HDD or when FortiAnalyzer or FortiGate Cloud is connected and enabled.
- Only applies to inspection on IMAP, POP3, SMTP, and MAPI protocols.
Protocol comparison between antivirus inspection modes
The following table indicates which protocols can be inspected by the designated antivirus scan modes.
| HTTP | FTP | IMAP | POP3 | SMTP | NNTP |
MAPI |
CIFS |
|
|---|---|---|---|---|---|---|---|---|
| Proxy | Yes | Yes | Yes | Yes | Yes | Yes |
Yes |
Yes* |
| Flow | Yes | Yes | Yes | Yes | Yes | No |
No |
Yes |
* Proxy mode antivirus inspection on CIFS protocol has the following limitations:
- Cannot detect infections within archive files
- Cannot detect oversized files
- Will block special archive types by default
- IPv6 is not supported
Other antivirus differences between inspection modes
Flow default mode uses a separate pre-filtering database for malware detection as opposed to the full AV signature database that Flow legacy and Proxy mode inspection use.
Proxy mode uses pre-scanning and stream-based scanning for HTTP traffic. This allows archive files that exceed the oversize limit to be uncompressed and scanned for infections.