Connect with us

Hi, what are you looking for?

SecurityWeekSecurityWeek

Cybercrime

Attacks Exploiting VMware vSphere Flaw Spotted One Week After Patching

A critical vulnerability affecting VMware vCenter Server, the management interface for vSphere environments, is being exploited in the wild. Attacks started roughly a week after VMware announced the availability of patches.

A critical vulnerability affecting VMware vCenter Server, the management interface for vSphere environments, is being exploited in the wild. Attacks started roughly a week after VMware announced the availability of patches.

In an advisory issued on May 25, VMware urged customers to immediately patch CVE-2021-21985 and warned that “the ramifications of this vulnerability are serious.”

VMware explained that the issue, discovered by Ricter Z of 360 Noah Lab, impacts the vSphere Client, specifically the Virtual SAN Health Check plugin, which is enabled by default in vCenter Server even if the plugin is not actually being used. An attacker with access to port 443 can exploit the flaw to execute commands with elevated privileges on the operating system that hosts vCenter Server.

A Chinese researcher who uses the online moniker “iswin” published a proof-of-concept (PoC) exploit on June 2. Threat intelligence firm Bad Packets reported seeing mass scanning activity targeting CVE-2021-21985 the next day.

Security researcher Kevin Beaumont also reported seeing scanning activity aimed at CVE-2021-21985 at around the same time, and on June 4 he confirmed that one of his honeypots was hacked.

VMware vCenter Server (CVE-2021-21985) exploited in the wild

Vietnamese security researcher Nguyen Jang has also released a PoC exploit, as well as technical details and a video showing the exploit in action. Ricter Z also detailed his findings on June 5. 

There are thousands of internet-exposed instances of vCenter Server.

Advertisement. Scroll to continue reading.

“Don’t connect vCenter directly to the internet by design, especially the appliance version,” Beaumont warned. “The appliance version is closed box Linux with no AV; somebody drops a webshell on box and now it’s permanently backdoored (even if patched) with no way to know, and it has ESXi access.”

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) also issued an alert to warn organizations about attacks targeting the vulnerability. 

This is not the first time threat actors have started exploiting a vCenter Server vulnerability shortly after it was patched. Earlier this year, scanning for systems impacted by CVE-2021-21972 began one day after fixes were released.

Cisco Talos reported last week that a piece of malware named Necro (aka Necromorph and FreakOut) has been exploiting CVE-2021-21972 since at least May. Necro is designed for DDoS attacks, network traffic exfiltration, and cryptocurrency mining.

Related: VMware Patches Critical Flaw Reported by Sanctioned Russian Security Firm

Related: VMware Patches Remote Code Execution Vulnerability in View Planner

Related: VMware Patches Critical Flaw in Carbon Black Cloud Workload

Written By

Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.

Click to comment

Daily Briefing Newsletter

Subscribe to the SecurityWeek Email Briefing to stay informed on the latest threats, trends, and technology, along with insightful columns from industry experts.

SecurityWeek’s Threat Detection and Incident Response Summit brings together security practitioners from around the world to share war stories on breaches, APT attacks and threat intelligence.

Register

Securityweek’s CISO Forum will address issues and challenges that are top of mind for today’s security leaders and what the future looks like as chief defenders of the enterprise.

Register

Expert Insights

Related Content

Vulnerabilities

Less than a week after announcing that it would suspended service indefinitely due to a conflict with an (at the time) unnamed security researcher...

Data Breaches

OpenAI has confirmed a ChatGPT data breach on the same day a security firm reported seeing the use of a component affected by an...

Cybercrime

The changing nature of what we still generally call ransomware will continue through 2023, driven by three primary conditions.

Cybercrime

Luxury retailer Neiman Marcus Group informed some customers last week that their online accounts had been breached by hackers.

Cybercrime

As it evolves, web3 will contain and increase all the security issues of web2 – and perhaps add a few more.

Cybercrime

A recently disclosed vBulletin vulnerability, which had a zero-day status for roughly two days last week, was exploited in a hacker attack targeting the...

Cybercrime

Satellite TV giant Dish Network confirmed that a recent outage was the result of a cyberattack and admitted that data was stolen.

Cybercrime

Zendesk is informing customers about a data breach that started with an SMS phishing campaign targeting the company’s employees.