w3w

In case you don't know, 127.0.0.1 is a standard for your local IP adress. Using that as a proxy means that every HTTP request is going through a program that is listening locally on port 54138. It can be some spyware, but it can also be something you installed, like old-fashion security program (ad blocking for example). I strongly suggest you check your system carefully (antivirus, ad-aware...) and, in case that's a spyware, you avoid using important credentials with this computer in the meantime.