What We Do
How we do it
Resources
TRU INTELLIGENCE CENTER
Our Threat Response Unit (TRU) publishes security advisories, blogs, reports, industry publications and webinars based on its original research and the insights driven through proactive threat hunts.
View Threat Intelligence Resources →
SECURITY ADVISORIES
Jun 03, 2022
UPDATE: CVE-2022-26134 – Confluence Zero-Day Vulnerability
THE THREAT June 3rd Update: Atlassian has released security patches to address this vulnerability. On June 2nd, 2022, Atlassian disclosed a critical vulnerability impacting the Confluence…
Read More
View all Advisories →
Company
ABOUT ESENTIRE
About Us
eSentire is The Authority in Managed Detection and Response Services, protecting the critical data and applications of 1200+ organizations in 75+ countries from known and unknown cyber threats. Founded in 2001, the company’s mission is to hunt, investigate and stop cyber threats before they become business disrupting events.
Read about how we got here
Leadership Work at eSentire
LATEST PRESS RELEASE
May 17, 2022
Cybersecurity Leader eSentire Continues Its Commitment to Rigorous Security Standards Earning PCI DSS Certification
Waterloo, ON, May 17, 2022 — eSentire, the Authority in Managed Detection and Response (MDR), maintains one of the most secure and robust IT environments of any MDR provider in the industry. To that end, eSentire today announced that it has received the Payment Card Industry Data Security Standard (PCI DSS) certification, considered one of the most stringent and comprehensive payment card…
Read More
Partners
PARTNER PROGRAM
e3 Ecosystem
We provide sophisticated cybersecurity solutions for Managed Security Service Providers (MSSPs), Managed Service Providers (MSPs), and Value-Added Resellers (VARs). Find out why you should partner with eSentire, the Authority in Managed Detection and Response, today.
Learn more
ECOSYSTEM PARTNER RESOURCES
Apply to become an e3 ecosystem partner with eSentire, the Authority in Managed Detection and Response.
Login to the Partner Portal for resources and content for current partners.
Search
Resources
Security advisories — Jun 07, 2021

Active Exploitation - CVE-2021-21985

2 minutes read
Speak With A Security Expert Now

THE THREAT

Security researchers have observed the active exploitation of the VMware vCenter vulnerability CVE-2021-21985 (CVSS: 9.8). Attacks have been identified as early as of June 4th. CVE-2021-21985 was publicly released on May 25th, 2021; exploitation allows for Remote Code Execution on the underlying operating system. In observed attacks, threat actors deployed web-shells on vulnerable internet facing vCenter servers.

Organizations that had not applied security patches to internet facing vCenter servers prior to June 4th are at an increased risk of exploitation. It is critical that organizations patch vulnerable assets as soon as possible.

What we’re doing about it

What you should do about it

Additional information

CVE-2021-21985 impacts VMware vCenter Servers. The vulnerability is due to the Virtual SAN Health Check plugin, which is enabled by default in vCenter Servers. An unauthenticated attacker with access to port 443 may exploit the vulnerability to execute code with elevated privileges on the underlying operating system that hosts a vulnerable vCenter server.

There is multiple functioning Proof-of-Concept (PoC) exploit code. The availability of both technical details and exploit code increases the likelihood of widespread exploitation. While initial attacks were identified on June 4th, scanning for vulnerable devices has been ongoing since at least May 3rd.

At this point, attacks exploiting CVE-2021-21985 are believed to be opportunistic in nature. Exposing vCenter servers directly to the internet is not standard practice, but there are a high number of devices that can be identified through internet scanning services such as Shodan. Currently, nearly 6,000 vCenter Servers show as internet facing on Shodan.

As attacks exploiting CVE-2021-21985 mature, it is expected that exploitation will move from opportunistic to targeted. If an organization’s vCenter server is not internet facing, threat actors that have already established a foothold on the network may still exploit the vulnerability to execute code with high privileges. This makes patching all vulnerable devices critical, even if they are not exposed to the internet.

Details on real-world attacks are still minimal. eSentire is actively tracking this topic for additional details and detection opportunities.

References:

[1] https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-21985
[2] https://twitter.com/GossiTheDog/status/1400868390726733831
[3] https://kb.vmware.com/s/article/83829

Join 100,000+ Security Leaders

Get notified when there's a new security advisory, and receive the latest news, intel and helpful tools & assets. You can unsubscribe anytime.

By clicking the button below I confirm that I have read and agree to the eSentire privacy policy.

View Most Recent Blogs