Symantec's MessageLabs division warns that more and more spammers are using shortened URLs to cover to evade spam filters. In the last couple of days, shortened URL spam shot up from nearly zero to over 2 percent of all spam.
The company says that the dozens of new URL-shortening services are allowing spammers to evade anti-spam tools that aim at Web domains known for sending spam. The services also inadvertently help spammers trick Internet users who would normally be wary of domain names like, say, Spammy.ru.
Spammers have long relied on redirecting services to mask their URLs. However, the URL-shortening services, which are free and require no registration, save them from having to register for a redirect site and, in some cases, solve a distorted-word puzzle (commonly called a “captcha”) to mask their domain name.