CVE-2021-44515: Security Advisory

This document addresses an authentication bypass vulnerability (CVE-2021-44515) in ManageEngine Desktop Central and provides an incident response plan if your system is affected.

Vulnerability ID: CVE-2021-44515
Severity: Critical
Update Release Date: 3rd December 2021
Fix Build:
i) For Enterprise-
For builds 10.1.2127.17 and below, upgrade to 10.1.2127.18
For builds 10.1.2128.0 to 10.1.2137.2, upgrade to 10.1.2137.3
ii) For MSP-
For builds 10.1.2127.17 and below, upgrade to 10.1.2127.18
For builds 10.1.2128.0 to 10.1.2137.2, upgrade to 10.1.2137.3

What was the problem?

An authentication bypass vulnerability in ManageEngine Desktop Central was identified and the vulnerability can allow an adversary to bypass authentication and execute arbitrary code in the Desktop Central server.

Note: As we are noticing indications of exploitation of this vulnerability, we strongly advise customers to update their installations to the latest build as soon as possible.

How do I check if my installation is affected?

We have developed an Exploit Detection Tool that will help you identify whether your installation has been affected by this vulnerability. You can download the tool here. Once you have downloaded the file, follow these steps:

  1. Extract the tool to \ManageEngine\UEMS_CentralServer\bin folder or \ManageEngine\DesktopCentral_Server\bin folder, whichever is applicable for you.
  2. Open command prompt with admin privilege and navigate to \ManageEngine\UEMS_CentralServer\bin folder or \ManageEngine\DesktopCentral_Server\bin folder.
  3. Run the command RCEScan.bat
  4. As shown in the screenshots below, if your installation is affected, you will be thrown the message "Exploit Detected". If your installation is safe, you will see the message "No Exploit Detected".

Here are some of the Indicators of Compromise (IOC) for this vulnerability (CVE 2021-44515):

  • Navigate to \lib and check if you can find the file aaa.zip ( md5 - 9809bdf6e9981fbc3ad515b731124342 ).
  • Navigate to \webapps\DesktopCentral\html and check if you can find the file help_me.jsp
  • Search the access log files at \logs\access_logs\access* for:
    • POST requests to the following URL: /STATE_ID/123/agentLogUploader
    • GET or POST requests to the following URL: /fos/statuscheck
  • For additional IOCs, please refer to this link.

Incident Response Plan

If affected:

1. Disconnect the affected system from your network.

2. Back up the Desktop Central database using these steps.

3. Format the compromised machine. Note: Before formatting the machine, ensure that you have backed up all critical business data.

4. Follow these steps to restore Desktop Central. 

  • The build version of the new installation should be the same as that of the database backup taken in step 2.
  • It is highly recommended to utilize a different machine for the new installation.

5. Mandatory step: Once the server is up and running, update Desktop Central to the latest build using the following steps:

i) Log in to your Desktop Central console, click on your current build number on the top right corner.

ii) You can find the latest build. Download the PPM and update.

Recommendation: Initiate a password reset for all services, accounts, Active Directory, etc. that has been accessed from the service installed machine. It is better if AD administrator passwords are also reset.

 

If not affected:

Mandatory step: Update Desktop Central to the latest build using the following steps:

i) Log in to your Desktop Central console, click on your current build number on the top right corner. ii) You can find the latest build. Download the PPM and update.

Note: This vulnerability is not applicable to Desktop Central Cloud.

For further assistance, please contact desktopcentral-security@manageengine.com

Keywords: Security Updates, Vulnerabilities and Fixes, CVE-2021-44515, authentication bypass