Technical Tip: How to block 'http_agent="Dart/3.3 (dart:io)"'

FortiWeb can block the traffic coming from 'http_agent="Dart/3.3 (dart:io)"'.

This can be achieved by using Custom Policy. Steps can be performed as below:

1. Navigate to Web Protection -> Advance Protection -> Custom Policy -> Custom Rule -> Create New and Give it name accordingly and select OK.
                                                   
   
2. After the rule is made, it is necessary to add Filter, so below the rule select Add Filter -> HTTP Header -> Select OK.
3. Once it further opens the HTTP Header menu, Set the Header Field as 'Predefined Header name' and Header Name as 'User-Agent'.
4. In Header Value Type set it as Regular Expression.
5. Inside Header Value, fill the code as '^Dart\/\d+\.\d+ \(dart:io\)$' (this can be modified based on the http_agent in the traffic logs) and select OK.
   
                                                
6. Once the rule is created, they proceed with creating a Custom Policy and Call the rule in that policy.
   
   
7. Once this is set up, call the Custom Policy in the required Web-protection profile, under Policy -> Web Protection Profile > Custom Policy, and select OK.

If the issue is not resolved then reach out to the support helpline with the required config and logs.

Related document:
Custom Policy