An anonymous reader writes "Microsoft engineer Terry Zink has discovered Android devices are being used to send spam. He has identified an international Android botnet and outlined the details on his MSDN blog. A closer look at the e-mails' header information shows all the messages come from compromised Yahoo accounts. Furthermore, they are also stamped with the 'Sent from Yahoo! Mail on Android' signature. Google has denied the allegations. 'The evidence does not support the Android botnet claim,' a Google spokesperson said in a statement. 'Our analysis suggests that spammers are using infected computers and a fake mobile signature to try to bypass anti-spam mechanisms in the email platform they're using.'"