Alex Zaharov-Reutt
Friday, 29 February 2008 06:56
Opinion and Analysis
Page 1 of 2
Uh-oh – it looks like Gmail addresses could soon be the originators of
spam - instead of being known for having a great spam filter, with the
news that Google’s CAPTCHA system to prevent automated sign-ups has
been busted.
Spam is still one of the Internet’s biggest unsolved problems, and despite Bill Gates promising a few years ago that Microsoft could solve the relentless spew of spam, junk email has only gotten worse!
One way that webmail sites offering free online email accounts have stopped spammers from using automated methods to set up free email accounts to send spam has been to use the CAPTCHA system often involving a few letters against a background with wavy lines or dots to make OCR (optical character recognition) difficult for non-humans.
The system is also widely used by websites offering forums or comment systems that users or readers can contribute to.
CAPTCHA stands for Completely Automated Public Turing test to tell Computers and Humans Apart, and for the most part, it has worked well. Even spammers have used the technique to send us all ‘pictures’ with text ads in them for all the usual spam products to defeat anti-spam algorithms.
But just as all locks are eventually defeated, so has the CAPTCHA system seen defeat – and this isn’t the first time.
As an example, Websense Security Labs noted that on Feb 6, 2008, the spammers defeated the Windows Live Mail
CAPTCHA system, and now the spammers have broken through
Google’s CAPTCHA defences.
So, how did they do it, and beyond simply the kudos of breaking through Google’s defences and the ability to send spam through Gmail, why did they do it? Please read onto page 2.
