Spam surges as Google's CAPTCHA falters

Techworld.com - The spread of CAPTCHA-breaking tools has resulted in a sudden surge in the use of blogging sites such as Google's Blogspot to host spam adverts, security vendor MessageLabs has reported.

According to the company's latest Intelligence report for October, the increasing level of spam pollution was found on free sites such as Blogspot and Mobileme, designed to exploit the high levels of trust afforded to content on branded sites.

The underlying mechanism is the ongoing collapse of traditional defense systems such as CAPTCHA (Completely Automated Public Turing Test to Tell Computers and Humans Apart), a variety of which have been broken over recent months.

Indeed, CAPTCHA's vulnerabilities has turned into one of the security themes of 2008, which began with the cracking open of Yahoo's much-vaunted system in January, continuing with a bot assault on Microsoft's equivalent, culminating in the use of Gmail to create fake user accounts in March.

The report paints a cascade effect, which has allowed a hole in CAPTCHA to let criminals set up large numbers of fake blogs and content, which are then used to feed bogus profiles to social networking systems. Messages and requests from these domains are a simple way around reputation-based antispam technology because they emanate from trusted sites not as aggressively filtered by such software.

"With the exploitation of Google Blogspot and MobileMe, we are again seeing two common spamming practices converge -- CAPTCHA breaking techniques and exploitation of free hosted services," said MessageLabs' Mark Sunner.

"The spammers are now taking it one step further and experimenting with the capabilities of social networking sites, like Bebo. As a result, users of social networking sites are receiving more buddy requests from fake profiles wishing to connect."

On a more upbeat note, the report does mention a parallel but less often commented upon spam trend -- perpetrators being successfully pursued by police forces around the globe.

Earlier this year, alleged professional MySpace spammers in the U.S. found themselves on the receiving end of a world record fine of $234 million, while more recently a notorious international operation based in New Zealand, Australia and the U.S. faced prosecution by authorities in those countries.

Earlier this month, MessageLabs agreed to a $695 million (£421 million) buy-out by Symantec.