Technical Tip: How to block HTTP request with empty value for specific HTTP header

There is a requirement to block HTTP requests with an empty value for a specific HTTP Header

For this article example, the requirement is to block HTTP requests with an empty value for the User-Agent HTTP Header.

Step 1: Go to WAF -> Applications (select the respective Applications) -> Advanced Applications -> Custom Rule.
Step 2: Create a new Custom Rule as below:

Step 3: Review the respective Attack Logs (Threat Analytics -> Attack Logs). The User-Agents HTTP Header shown in the Data Packet Details has no value (empty), and the request was blocked.

Related documents:
Custom Rule