onetwoseven

Can someone give me a hint about sftp part?
I tried creating links, but i limited in web root (www), so i didn’t manage browse something interesting.
And i tried uploading shell and giving 777 to it, but getting 403 all the time.
What am i missing?

EDIT: Working only in sftp tunneled my vision, didn’t thought how different environments may interact with same object.
Moved on, but did not managed uploading reverse/command shell from sftp.