All he is doing is sending you some free traffic
Well, yeah, except that his only possible motive is to make his own site look good, right?
Kaks sent me the the name of the offending page; it's now got a different victim. Note this from the initial post:
the homepage of site.com has a very sly "500 internal server error"
This can only be intentional. If you go to the front page in the normal way, you get what looks like a legitimate 500 page (cut-and-paste, so it's all the same size):
Oops! An Error Occurred
The server returned a "500 Internal Server Error".
Something is broken. Please e-mail us at [email] and let us know what you were doing when this error occurred. We will fix it as soon as possible. Sorry for any inconvenience caused.
That [email] is not obfuscation on my part; it's the literal text of the page.
But wait! If you use a browser that allows UA spoofing and feed it the googlebot's UA string, you instead get a perfectly blank page. (Nothing at all in the source.) Same thing if you go via a UA-spoofing site.
And if, like me, you pursue the next hunch and ask for
example.biz/index.php
you first get redirected to
example.biz/index.php/
and then you get what looks like a genuine error:
Fatal error: Call to a member function getDirectory() on a non-object in /var/www/APL/src/APM/MainBundle/Controller/DefaultController.php on line 104
The offending domain lives at-- surprise, surprise-- AWS. Some further snooping reveals that three www sites share an IP (54.200.etcetera), and their names suggest they're all related except one's in Portuguese (the subject of this thread) while the other two are English and German respectively. And yup, they all appear to have the same whois information.
A final tidbit again gleaned from free lookup: The current victim site lists one recent RSS feed-- and by amazing coincidence it's the same page that is now being iframed.
A site: search in google naming the offending site comes up cold. So how did people find the site in the first place?