From Wiktionary, the free dictionary
The word sheesh after rot-13 encoding. Coined on Usenet in the 1990s.
furrfu
- (Internet slang) sheesh
2002, Linz, “miscarrage”, in misc.kids.pregnancy (Usenet):Oh furrfu! I have enough to worry about!
2004, Richard P. Grant, “I told you that URLs were vulnerable...”, in uk.comp.sys.mac (Usenet):Oh furrfu. Don't come that intuititive[sic] shite here, Peter. *Nothing* is completely intuitive, *everything* needs some learning.