It seems to be adding a lot to the loading time. And "iframe attacks" are a common and very nasty distribution mechanism for malware - I wouldn't know how to tell an innocent one from a malicious one. We can't tell just by looking at what comes out of Mudcat whether Max or some Chinese or NSA hacker put it there.

2345.com seems to have no redeeming value from what I can see, so my bet is this is malicious. I'd block it if I could, but like Bill I can't see how.