Lemon Duck Cryptojacking Botnet Changes Up Tactics

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The Lemon Duck cryptocurrency-mining botnet has added the ProxyLogon group of exploits to its bag of tricks, targeting Microsoft Exchange servers.
 
That’s according to researchers at Cisco Talos, who said that the cybercrime group behind Lemon Duck has also added the Cobalt Strike attack framework into its malware toolkit and has beefed up anti-detection capabilities. On the latter front, it’s using fake domains on East Asian top-level domains (TLDs) to hide command-and-control (C2) infrastructure.
 
Lemon Duck targets victims’ computer resources to mine the Monero virtual currency, with self-propagating capabilities and a modular framework that allows it to infect additional systems that become part of the botnet. It has been active since at least the end of December 2018, and Cisco Talos calls it “one of the more complex” mining botnets, with several interesting tricks up its sleeve.
 
For instance, Lemon Duck has at least 12 different initial-infection vectors – more than most malware, with Proxylogon exploits only the latest addition. Its existing capabilities ranged from Server Message Block (SMB) and Remote Desktop Protocol (RDP) password brute-forcing; targeting the RDP BlueKeep flaw (CVE-2019-0708) in Windows machines; targeting internet-of-things devices with weak or default passwords; and exploiting vulnerabilities in Redis (an open-source, in-memory data structure store used as a database, cache and message broker) and YARN Hadoop (a resource-management and job-scheduling technology) in Linux machines.
 
“Since April 2021, Cisco Talos has observed updated infrastructure and new components associated with the Lemon Duck that target unpatched Microsoft Exchange Servers and attempt to download and execute payloads for Cobalt Strike DNS beacons,” according to an analysis released Friday.
 
Cisco Talos researchers previously observed an increase in DNS requests connected with Lemon Duck’s C2 and mining servers last August, with the attacks mainly targeting Egypt, India, Iran, the Philippines and Vietnam. In the latest rash of attacks, which began in April, the group has changed up its geographic targets to focus primarily on North America, followed by Europe and Southeast Asia, and a handful of victims in Africa and South America.

Read more: Lemon Duck Cryptojacking Botnet Changes Up Tactics | Threatpost