We are seeing a lot of SpamTools now. These programs are installed on victim machines secretly, where they proceed to harvest email addresses. The harvested addresses are sent to the SpamTools master and used for mass mailings. In most cases, such spammer utilties are then de-installed automatically. The result? When antivirus and anti-spam vendors do not. receive mass. mailings directly, it takes longer for the security community to react.”]
Source: https://securelist.com/spammers-hide-from-antivirus-vendors/29965/