Pretty much all spam on the globe in the last quarter of 2017 was sent by two botnets, says McAfee in a report (PDF). The botnets are called Necurs and Gamut, and can be rented by cyber criminals to sent out Spam, phishing mails, ransomware and other types of malware.

The two botnets have been responsible for 97% of all spam worldwide. With a market share of 60%, the Necurs botnet was the most used, followed by the Gamut botnet with a market share of 37%. Lethic, Darkmailer and unmentioned botnets each account for a market share of 1% each. According to McAfee, the Necurs botnet is currently the largest spam bot net in the world, mentions myce today.

A botnet is a group of computers connected in a coordinated fashion for malicious purposes. Each computer in a botnet is called a bot. These bots form a network of compromised computers, which is controlled by a third party and used to transmit malware or spam, or to launch attacks.

“The infected computers operate in a peer-to-peer model, with limited communication between the nodes and the control server,” McAfee explains.

In the last quarter of 2017, ransomware variants GlobalImposter, Locky and Scarab were distributed through the Necurs botnet. Through the Gamut botnet, emails to recruit money-mules and phishing mails were sent.