Spammers create short URL systems to beat security
Spammers have started setting up bogus URL shortening services to act as relay points for traffic generated by their emails, Symantec’s MessageLabs divison has reported in its May 2011 Intelligence Report.
Criminals have for some time embedded URLs created by legitimate URL shortening services as a way of attempting to fool spam filters, which see a real URL rather than a suspect one. Following the link leads to a spam website.
Because this trick is now known to security companies and short URL companies, Symantec has noticed the rise of a new evasion technique that works by embedding a legitimate short URL, which in turn points to a short URL system set up by the spammers. This then hands traffic to the final site, introducing an extra layer to beat filters.
