NEW OPEN REDIRECTER I just noticed a new (for me) yahoo redirecter in spam received eur.rd.yahoo.com
On a hunch, I also tried things like:
uk.rd.yahoo.com it.rd.yahoo.com de.rd.yahoo.com
which are all open redirecters. There are sure to be more of these using other country code prefixes.
So for those using SpamCopURI you probably need this in your spamcop_uri.cf:
open_redirect_list_spamcop_uri rd.yahoo.com *.rd.yahoo.com
I'd recommend Eric to add this to the default SpamCopURI configuration on the next release, along with others like
open_redirect_list_spamcop_uri drs.yahoo.com open_redirect_list_spamcop_uri ads.msn.com g.msn.com
which aren't currently in the defaults.
NEW SPAMMER TRICK FOR URLS Having added the new redirection service, I found that SpamCopURI 0.16 didn't pick up the url shown at the end of this message. The reason is that resolving the URL through the SpamCopURI gives a HTTP/1.1 403 Forbidden. As the response code does not begin with a 3 (= redirection), the URL is assumed to be the final one. The domain which is subjected to lookup in sc.surbl.org is (after normalizing to the register level) is yahoo.com. So this one gets past SpamCopURI.
Howver, in a commonly used browser, the url redirects to the spamvertized site without difficulty.
I cannot help thinking that this url has been carefully crafted to avoid processing by SpamCopURI but still be acceptable to a browser. (That's a terrifying thought).
In order to obtain the 302 code the browser sees 2 things are necessary: 1. Add a / before the * (That is the correct format for yahoo redirection) 2. Change the hTtP:\ to hTtP:// (The mixed case is not a problem)
While the second one is a general case (other redirection services could be abused in the same way by browser loopholes) the first one is a very specific browser loophole that applies only to yahoo redirection.
Here's the URL. I didn't even munge it, since it should get past the filters.
<a href="http://eur.rd.yahoo.com/electric\croydon\laity\otherworldly\phonetic\e xplicit\mountaineer\integrable\isadore\wangle\zounds\contumacy\embedded\sang uine\arrangeable\duane\malarial\bremsstrahlung\freshmen\windup\spoon\accompa ny\soldier\throb\boil\harrisburg\quartz\throne\giddap\waistcoat\guzzle\whoop \abreast\corral\latrobe\ct\castor\gallup\click\cretinous\alcoa\lysine\wheelc hair\levy\embedded\faint\floodlight\elmer\fiesta\pistachio\pulp\suppress\fle awort\flick\topcoat\brain\prom\bill\knife\serene\*hTtP:\\7Wv2eg82o19X.zbxra1 .com/gp/iNdeX.ASP?id=BW" target="_blank"><b>hit this</b></a>
John