Massive ransomware operation targets VMware ESXi: How to protect from this security hazard


These ransomware infections on VMware ESXi software are due to a vulnerability that has existed since 2021. Discover the most targeted nations and how to secure your organization.

Ransomware on a screen and a person with his head in his hands.

Image: Adobe Stock Jump to: How does this ransomware attack run? CVE-2021-21974 is a vulnerability affecting OpenSLP as utilized in VMware ESXi. Effective exploitation of that vulnerability permits an attacker to execute arbitrary code, and exploits for this vulnerability can be found in various open sources given that May 2021.

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The French federal government’s Computer system Emergency Response Group CERT-FR was the very first to raise an alert on ransomware exploiting this vulnerability on Feb. 3, 2023, rapidly followed by French hosting provider OVH.

Attackers can exploit the vulnerability remotely and unauthenticated through port 427 (Service Area Procedure, SLP), which is a protocol that most VMware customers do not use.

The ransomware secures files with the following extensions on the affected systems:. vmdk,. vmxf,. vmsd,. vmsn,. vmss,. vswp,. nvram and.vmem. Then, it attempts to close down the virtual makers by eliminating the VMX process to unlock the files.

A text note is left after encryption is done (Figure A), requesting ransom that should be paid in Bitcoin cryptocurrency within three days.

Figure A

Ransom note left on a targeted device. Image: Twitter. Ransom note left on a targeted gadget. The ransomware threat actor behind this attack is not understood, as the malware appears to be a new ransomware. OVH has actually reported that according to numerous security researchers, the file encryption cipher used in the ransomware is the same as what was utilized in the leaked Babuk malware code from September 2021, although the code structure is various.

The Babuk code that leaked in 2021 has been utilized to create other malware that typically targets ESXi systems, but it appears prematurely to draw a conclusive conclusion as to the attribution of that brand-new malware, which has been dubbed ESXiArgs by security researchers.

France and U.S. are the greatest targets

Censys Browse, an online tool for exploring internet-connected devices, reveals that more than 1,000 servers have actually been effectively hit by the ransomware, mostly in France, followed by the U.S. and Germany.

At the time of composing, more than 900 servers were jeopardized in France, while around 400 servers in the U.S. were struck.

A lot more systems might be susceptible and not yet assaulted. The Shadowserver Foundation reports that around 27,000 circumstances may be vulnerable, according to the version of its VMware software.

How to safeguard your company from this ransomware danger

For systems running unpatched versions of VMware ESXi, the absolute priority is to cut the SLP service if it runs. The vulnerability can only be made use of by means of that service, so if it is closed, the system can not be attacked by means of this vector.

The next step includes reinstalling the hypervisor in a variation supported by VMware– ESXi 7.x or ESXi 8.x– and applying all security patches.

Finally, all administration services ought to be safeguarded and just readily available in your area. In case there is a need for remote gain access to, VPN with multi-factor authentication or IP filtering must be utilized.

Jan Lovmand, chief innovation officer of BullWall, a cybersecurity company concentrated on avoiding ransomware attacks, informed TechRepublic more about the vulnerability.

“A spot has been offered from VMware given that February 2021 when the vulnerability was discovered,” Lovmand stated. “This simply goes to demonstrate how long it takes numerous organizations to navigate to patch internal systems and applications, which is simply among many reasons why the criminals keep discovering their method. The attack surface area is huge, and preventative security options can be bypassed in a scenario like this if the vulnerability has actually not been patched.”

Lovmand also stressed the value of covering your networks.

“It’s 50-50 chances that your company will be effectively struck with ransomware in 2023,” he said. “Security options can not protect unpatched networks.”

How to recuperate from this ransomware threat

Security scientists Enes Somnez and Ahmet Aykac have actually supplied a option to recuperate in case a system has actually been attacked by this ransomware.

The researchers discuss that the ransomware encrypts little files like.vmdk and.vmx but not the server-flat. vmdk file, which consists of the actual data. Utilizing this file, it’s possible to do a fallback and recuperate info from the system.

Julien Levrard, chief info gatekeeper from OVHCloud, wrote that the approach recorded by Somnez and Aykac has actually been checked by OVH in addition to lots of security experts with success on several impacted servers, with a success rate of 2/3. He included that “this procedure requires strong skills on ESXi environments.”

Disclosure: I work for Trend Micro, but the views revealed in this article are mine.

Check out next: Spot management policy (TechRepublic Premium)


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