Posted by skor on July 10, 2007 at 4:17am
From: http://news.zdnet.co.uk/security/0,1000000189,39287905,00.htm
A new Trojan horse that sends spam through Hotmail and Yahoo email accounts has antivirus companies worried that the commonly used "captcha" system, used to prove new members are real people, may have been compromised
...
The Trojan uses automatically generated accounts, suggesting that spammers have found a way to bypass the captcha systems
Hopefully this is highly customized towards the Yahoo/Windows Live captchas, which actually look pretty similar. They both distort the text in a wave pattern and add only one or two background lines.