The company, Clearswift, claims the latest trend in spam is actively encouraging people to spy on people they know, and has recently intercepted messages with subjects such as "MONITOR your Kids on the Internet with Spy Software".
That message advertises software that allows its users to record e-mails and instant messages, as well intercepting passwords. Clearswift's Asia-Pacific managing director, Chy Chuawiwat, says the practise represents a genuine threat to privacy.
"The spam is encouraging people to spy on people they know, by tricking them into opening an attachment. This is a real threat to the personal privacy of individuals and to the security of information in organisations," he said.
The spyware is particularly unpalatable because it appears to come from someone you know, and therefore trust, he added.
More traditional spam, such as "scam messages", healthcare and porn still managed to increase in September.
