For two years a malware called Lemon Duck has been infecting computers for Monero mining. In the last two months, its activity has increased at an alarming rate.
Cisco Talos researchers have been monitoring the Lemon Duck botnet since December 2018. Since August they have seen a large increase in the number of communications with the servers that control Lemon Duck activity.
Cisco Talos notes that malware is designed to spread in many ways.
Like many other malware groups that have spread since the beginning of the Coronavirus pandemic, Lemon Duck also uses COVID-19 phishing email.
The emails are very simplistic about the pandemic ("COVID-19" or "The Truth of COVID-19") and contain an infected Microsoft Word document.
Mining cryptocurrencies like Monero can be a very intensive process. The harder the processors work, the more heat they generate. Without sufficient cooling to compensate for the heating, the hardware is at risk.
The criminals behind Lemon Duck want to make sure their operation is profitable. This is why Lemon Duck checks infected machines and shuts them down.