Using ASM to Restrict File Uploads to PDF Only

Answer provided by F5 Employee.

1. Detecting file upload
2. Validating the file type to be uploaded using ASM: a.Identify the parameter name i.Parse the HTTP request using an inspection tool (e.g. HTTPWatch) ii.Search the ASM logs iii.Ask the Dev team b.Add the parameter to the configuration by: i.Manually configuring it in the Parameters section ii.Searching the Policy Building  Manual  Entity learning section c.Create the parameter i.Parameter Level: Global (though you can be specific and associate to a web object) ii.Parameter Value Type: User-Input iii.Data Type  Check Max Length: Give a number (e.g. 100) iv.Data Type  Regular expression: (?i).(gif|jpeg|jpg|bmp) v.(?i) – ignore case sensitivity
3. Add additional file types inside parenthesis and separate by | i.Click on Create ii.Apply the policy iii.Validate the enforcement iv.Upload a different file extension v.Reporting  Requests: verify that the following violation was detected: vi.Parameter value does not comply with regular expression