Cheerscript plants double-extortion malware on ESXi servers. Credit: Towfiqu Aham / Getty Images Researchers at Trend Micro have discovered some new Linux-based ransomware that’s being used to attack VMware ESXi servers, a bare-metal hypervisor for creating and running several virtual machines (VMs) that share the same hard drive storage. Called Cheerscrypt, the bad app is following in the footsteps of other ransomware programs—such as LockBit, Hive and RansomEXX—that have found ESXi an efficient way to infect many computers at once with malicious payloads.Roger Grimes, a defense evangelist with security awareness training provider KnowBe4, explains that most of the world’s organizations operate using VMware virtual machines. “It makes the job of ransomware attackers far easier because they can encrypt one server—the VMware server—and then encrypt every guest VM it contains. One compromise and encryption command can easily encrypt dozens to hundreds of other virtually run computers all at once.”“Most VM shops use some sort of VM backup product to back up all guest servers, so finding and deleting or corrupting one backup repository kills the backup image for all the hosted guest servers all at once,” Grimes adds.Cheerscrypt gang uses “double extortion” The Trend Micro researchers— Arianne Dela Cruz, Byron Gelera, McJustine De Guzman, and Warren Sto. Tomas—explain in a company blog that after acquiring an input parameter specifying an encryption path, Cheerscrypt issues a command terminating all VM processes to make sure it can encrypt all VM-related files. The gang behind Cheerscrypt uses a “double extortion” technique to extract money from its targets, the researchers explain. “Security Alert!!!” the attackers’ ransom message declares. “We hacked your company successfully. All files have been stolen and encrypted by us. If you want to restore your files or avoid file leaks, please contact us.”The researchers note that Cheerscrypt uses public/private encryption technology to scramble the files on a target’s server. The ransomware’s executable file contains a public key, while the attacker holds the private key needed to decrypt the files encrypted with the public key. Files are encrypted using the SOSEMANUK stream cipher, while ECDH is used to create the SOSEMANUK key. Expect malicious actors to upgrade malware to expand breach scopeESXi is widely used in enterprise settings for server virtualization, the researchers explained. Therefore, it’s a popular target for ransomware attacks. Because it is a means to swiftly spread the ransomware to many devices, they add, organizations should thus expect malicious actors to upgrade their malware arsenal and breach as many systems and platforms as they can for monetary gain.“As more organizations improve their security by adopting multi-factor authentication with biometrics, they are effectively locking the front door that has been the vulnerability of choice for hackers,” says John Gunn, CEO of Token. “That doesn’t mean bad actors will go away. They will instead shift their methods to attacks such as this.” Related content news Top cybersecurity product news of the week New product and service announcements from Coro, Descope, Genetec, Varonis, Cloudbrink, Databarracks, and Security Journey By CSO staff Dec 07, 2023 22 mins Generative AI Generative AI Machine Learning news analysis Attackers breach US government agencies through ColdFusion flaw Both incidents targeted outdated and unpatched ColdFusion servers and exploited a known vulnerability. By Lucian Constantin Dec 06, 2023 5 mins Advanced Persistent Threats Cyberattacks Vulnerabilities news BSIMM 14 finds rapid growth in automated security technology Embrace of a "shift everywhere" philosophy is driving a demand for automated, event-driven software security testing. By John P. Mello Jr. Dec 06, 2023 4 mins Application Security Network Security news Almost 50% of organizations plan to reduce cybersecurity headcounts: Survey While organizations are realizing the need for knowledgeable teams to address unknown threats, they are also looking to reduce their security headcount and infrastructure spending. By Gagandeep Kaur Dec 06, 2023 4 mins IT Jobs Security Practices Podcasts Videos Resources Events SUBSCRIBE TO OUR NEWSLETTER From our editors straight to your inbox Get started by entering your email address below. Please enter a valid email address Subscribe