as poijted out already magika is useful for good file type analysis. also, scan thoroughly for viruses, potebtially using multiple engines. now this can be tric

as poijted out already magika is useful for good file type analysis. also, scan thoroughly for viruses, potebtially using multiple engines. now this can be tricky depending on the confidentiality of the uploaded files so take good care not to submit them to sandboxes, av platforms etc. if not allowed. i would really recommend it though. if you want to get into the nitty grit of filetype abuse, to learn how to possibly detect that good. ange albertini's work on polymorphic filetypes and the ezine poc||gtfo as well as lots of articles by AV code devs are available. its really hard problem and also depends a lot on what program is interpreting the files submitted. if its some custom tool.there might even be unique vectors to take into account. fuzzing and penteting the upload form and any tools handing these files can shed light on those issues potentially. (edit: fat fingers)