A new bot can crack defenses erected by Microsoft to keep spammers from creating large numbers of accounts on its Live Hotmail service within seconds, a security researcher said Friday.
Dan Hubbard, vice president of security research at Websense, said the bot broke Live Hotmail’s CAPTCHA (Completely Automated Public Turing Test to Tell Computers and Humans Apart) within six seconds, on average. CAPTCHA is the name given to the distorted, scrambled characters that many Web services require users to decipher and type in to create a new account; the tests are meant to block automated account registration by spammers and malware authors.
The bot, Hubbard acknowledged, is similar to one Websense uncovered in February.
“In the past, though, it was kind of questionable whether the CAPTCHA breaking was automated,” Hubbard said Friday, noting that there had been some evidence that spammers were paying people to decode and type in the CAPTCHA characters. “But the bot’s breaking [CAPTCHA] in six seconds, so it’s definitely automated.”
In a long post to the Websense blog Thursday, Sumeet Prasad — “our CAPTCHA expert,” said Hubbard — provided technical details of how the bot automatically registers Live Hotmail accounts and then immediately begins using those accounts to spew spam.
The bot’s total response time — how long it takes the program to grab a CAPTCHA image, analyze it and return with the correct code — is considerably shorter than that of earlier such bots, said Prasad in the blog.
One in every eight to 10 attempts to create a Live Hotmail account is successful, added Prasad, meaning that the success rate is 10% to 15%.
Posted under Security, Tech News
This post was written by Nicki on April 16, 2008
A new bot can crack defenses erected by
Spam is an annoyance most of us have just had to deal with on some level if we use email. As an IT Manager for a local company, I have dealt with spam at the prevention level as well as the user level, both with their own frustrations. Although, I must admit some level of satisfaction when able to block certain spam. Of course, that satisfaction is often short-lived and much like trying to keep your house dry by sitting on the roof holding an umbrella.
Hackers have launched a widespread “pump-and-dump” stock spam campaign using PDF files, anti-virus researchers have warned.



