CVE-2021-21986 - Improper Authentication

Severity

98%

Complexity

39%

Confidentiality

98%

The vSphere Client (HTML5) contains a vulnerability in a vSphere authentication mechanism for the Virtual SAN Health Check, Site Recovery, vSphere Lifecycle Manager, and VMware Cloud Director Availability plug-ins. A malicious actor with network access to port 443 on vCenter Server may perform actions allowed by the impacted plug-ins without authentication.

CVSS 3.1 Base Score 9.8. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

CVSS 2.0 Base Score 9.9. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (AV:N/AC:L/Au:N/C:C/I:C/A:C).

Demo Examples

Improper Authentication

CWE-287

The following code intends to ensure that the user is already logged in. If not, the code performs authentication with the user-provided username and password. If successful, it sets the loggedin and user cookies to "remember" that the user has already logged in. Finally, the code performs administrator tasks if the logged-in user has the "Administrator" username, as recorded in the user cookie.


               
}
}
ExitError("Error: you need to log in first");
);
);
DoAdministratorTasks();

Unfortunately, this code can be bypassed. The attacker can set the cookies independently so that the code does not check the username and password. The attacker could do this with an HTTP request containing headers such as:


               
[body of request]

By setting the loggedin cookie to "true", the attacker bypasses the entire authentication check. By using the "Administrator" value in the user cookie, the attacker also gains privileges to administer the software.

Improper Authentication

CWE-287

Overview

First reported 3 years ago

2021-05-26 15:15:00

Last updated 3 years ago

2021-08-24 10:59:00

Affected Software

VMware VCenter Server 6.5

6.5

VMware vCenter Server 6.5 Update 1

6.5

VMware vCenter Server 6.5 Update 1b

6.5

VMware vCenter Server 6.5 Update 1c

6.5

VMware vCenter Server 6.5 Update A

6.5

VMware vCenter Server 6.5 Update B

6.5

VMware vCenter Server 6.5 Update C

6.5

VMware vCenter Server 6.5 Update D

6.5

VMware vCenter Server 6.5 Update E

6.5

VMware vCenter Server 6.5 Update F

6.5

VMWare vCenter Server 6.7 U2c

6.7

VMWare vCenter Server 6.7 U2a

6.7

VMWare vCenter Server 6.7 U2

6.7

VMWare vCenter Server 6.7 U1b

6.7

VMWare vCenter Server 6.7 U1

6.7

VMWare vCenter Server 6.7 d

6.7

VMWare vCenter Server 6.7 b

6.7

VMWare vCenter Server 6.7 a

6.7

VMWare vCenter Server 6.5 U1d

6.5

VMWare vCenter Server 6.5 U1e

6.5

VMWare vCenter Server 6.5 U1g

6.5

VMWare vCenter Server 6.5 U2

6.5

VMWare vCenter Server 6.5 U2b

6.5

VMWare vCenter Server 6.5 U2c

6.5

VMWare vCenter Server 6.5 U2d

6.5

VMWare vCenter Server 6.5 U2g

6.5

VMWare vCenter Server 6.5 U3

6.5

VMWare vCenter Server 6.7

6.7

VMWare vCenter Server 6.7 U3

6.7

VMWare vCenter Server 6.5 U3d

6.5

VMWare vCenter Server 6.7 U3a

6.7

VMware Cloud Foundation

Stay updated

ExploitPedia is constantly evolving. Sign up to receive a notification when we release additional functionality.

Get in touch

If you'd like to report a bug or have any suggestions for improvements then please do get in touch with us using this form. We will get back to you as soon as we can.