Microsoft Warns of ‘Evolving’ LemonDuck Mining Malware Targeting Linux and Windows Machines

The threat intelligence team for Microsoft’s 365 Defender security suite recently focused on an example of “modern mining malware infrastructure,” describing how “Anything that can gain access to machines — even so-called commodity malware — can bring in more dangerous threats.”

Specifically, it offered a case study of LemonDuck. The blog post’s title? “When coin miners evolve…” Today, beyond using resources for its traditional bot and mining activities, LemonDuck steals credentials, removes security controls, spreads via emails, moves laterally, and ultimately drops more tools for human-operated activity.

LemonDuck’s threat to enterprises is also in the fact that it’s a cross-platform threat. It’s one of a few documented bot malware families that targets Linux systems as well as Windows devices. It uses a wide range of spreading mechanisms — phishing emails, exploits, USB devices, brute force, among others — and it has shown that it can quickly take advantage of news, events, or the release of new exploits to run effective campaigns… Notably, LemonDuck removes other attackers from a compromised device by getting rid of competing malware and preventing any new infections by patching the same vulnerabilities it used to gain access… LemonDuck spreads in a variety of ways, but the two main methods are (1) compromises that are either edge-initiated or facilitated by bot implants moving laterally within an organization, or (2) bot-initiated email campaigns.

LemonDuck acts as a loader for many other follow-on activities, but one if its main functions is to spread by compromising other systems. Since its first appearance, the LemonDuck operators have leveraged scans against both Windows and Linux devices for open or weakly authenticated SMB, Exchange, SQL, Hadoop, REDIS, RDP, or other edge devices that might be vulnerable to password spray or application vulnerabilities… Other common methods of infection include movement within the compromised environment, as well as through USB and connected drives. These processes are often kicked off automatically and have occurred consistently throughout the entirety of LemonDuck’s operation.