cbcvebase.
CVE-2021-21985
published 2021-05-26

CVE-2021-21985: The vSphere Client (HTML5) contains a remote code execution vulnerability due to lack of input validation in the Virtual SAN Health Check plug-in which is…

PriorityP1100critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
KEVITWEXPLOITRansomwareInitial access
CISA Known Exploited Vulnerabilitydue 2021-11-17
Exploited in the wild
EPSS
100.00%
100.0th percentile
The vSphere Client (HTML5) contains a remote code execution vulnerability due to lack of input validation in the Virtual SAN Health Check plug-in which is enabled by default in vCenter Server. A malicious actor with network access to port 443 may exploit this issue to execute commands with unrestricted privileges on the underlying operating system that hosts vCenter Server.

Affected

5 ranges
VendorProductVersion rangeFixed in
vmwarecloud_foundation>= 3.0 < 3.10.2.13.10.2.1
vmwarecloud_foundation>= 4.0 < 4.2.14.2.1
vmwarevcenter_server
vmwarevcenter_server
vmwarevcenter_server

Detection & IOCsextracted from sources · hover to see the quote

port443
snort
57720
  • Monitor for active scanning/exploitation attempts targeting VMware vSphere Client (vCenter Server) on port 443; GreyNoise tagged IPs sending requests exploiting CVE-2021-21985 as 'Malicious' and IPs checking for its existence as 'Unknown'.
  • Threat actors were actively scanning for internet-exposed VMware vCenter servers vulnerable to CVE-2021-21985 shortly after patch release; monitor for mass scanning activity against vCenter endpoints.
  • ·The Virtual SAN Health Check plug-in is enabled by default in vCenter Server, meaning all default-configuration vCenter deployments are affected without any additional attacker precondition beyond network access to port 443.

CVSS provenance

nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvdv2.010.0CRITICALAV:N/AC:L/Au:N/C:C/I:C/A:C
vulncheck9.8CRITICAL
cisa9.8CRITICAL
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