More secure file validation?

[madshargreave]

Hi

How can I safely validate avatars uploaded by users?

It seems to me that a user could easily just rename a virus.exe to avatar.png and pass the default validation.

Any ideas?

[cichaczem]

I had the same problem so I built small lib checking MIME type of given file: https://gist.github.com/cichaczem/c3fb262b7cd284d75a46a77d1ff6506d