CVE-2021-21973KEV · OVERDUE

VMware vCenter Server and Cloud Foundation Server Side Request Forgery (SSRF) Vulnerability

Medium · published February 24, 2021

Patch now

The score understates this — it's already being exploited

CVSS calls it medium at 5.3. It is confirmed in active exploitation. It sits in the 99.8th percentile for exploit probability.

1678
days past CISA
deadline
CVSS v3.1
5.3
EPSS
88%
Percentile
99.8
In the wild
Confirmed
What it is

⚠️ The vSphere Client is letting slip through the cracks! An SSRF vulnerability in the vCenter Server plugin allows attackers to sneakily access sensitive information with just a simple POST request! 🔍 Think of it like a delivery service that doesn't check the contents of every package it accepts. If a malicious actor sends in a request dressed up as a legitimate delivery, they could gain access to confidential information as if they were receiving a special package just for them. An attacker with network access to port 443 could exploit this vulnerability to reveal sensitive data from the vCenter Server. This could lead to unauthorized information disclosure, potentially compromising your environment and exposing your organization to further risks.

Put simply

Think of it like a delivery service that doesn't check the contents of every package it accepts. If a malicious actor sends in a request dressed up as a legitimate delivery, they could gain access to confidential information as if they were receiving a special package just for them. This SSRF vulnerability arises from improper validation of URLs in the vCenter Server plugin, allowing unauthorized requests to be processed. This means a crafted POST request can trick the server into revealing internal resources, opening the door to sensitive information.

What to do

An attacker with network access to port 443 could exploit this vulnerability to reveal sensitive data from the vCenter Server. This could lead to unauthorized information disclosure, potentially compromising your environment and exposing your organization to further risks. To protect your systems, ensure you update to the patched versions: VMware vCenter Server (7.0 U1c, 6.7 U3l, 6.5 U3n) and VMware Cloud Foundation (4.2, 3.10.1.2). Additionally, review your network access policies and monitor traffic on port 443 for any suspicious activities. You've got this! Implement these fixes, and you'll fortify your defenses in no time! 🛡️

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.88012 · 99.8th percentile
Published
2021-02-24T16:42Z
KEV added
2022-03-07 · due 2022-03-21
EPSS history
Timeline
  • 07 MAR 00:00Z
    Added to CISA KEV — remediate by Mar 21
    kev
  • 24 FEB 16:42Z
    The vSphere Client (HTML5) contains an SSRF (Server Side Request Forgery) vulnerability due to improper validation of URLs in a vCenter Server plugin
    cvelistv5