Unique filenames for uploads

I created a site that has many, many users who post articles daily. I have discovered that Word Press does not automatically rename uploaded files to a unique name such as the date and time (which it should). My users are accidentally overwriting each other’s pictures. Is there a solution to this? I have medium experience writing PHP scripts, but not sure where in the inline uploading file I would find the place to make a fix. This site is critical for me. Please help.