Magniber Ransomware Weaponize JavaScript to Attack Windows Users

Recently, the security researchers at HP’s threat intelligence team have discovered a malicious campaign in which the threat actors are delivering Magniber ransomware and with the help of fraudulent security updates targeted Windows Home users.

A number of fake websites were created by threat actors in September 2022. On those fake websites, fraudulent antivirus and security updates for Windows 10 were promoted and distributed by the threat actors.

A complex infection chain begins with the deployment of the file-encrypting malware that gets downloaded as JavaScript.

In order to receive a decryption tool to be able to recover home users’ files, Magniber ransomware’s operators demanded a payment of up to $2,500 from the victims. 

Targeted Versions

This strain focuses exclusively on Windows 10 and Windows 11 builds that are currently available for download. Here below we have mentioned all the targeted versions of Windows 10 and Windows 11:-

Version Code	Name	Release Date
17134	Windows 10, Version 1803	April 30, 2018
17763	Windows 10, Version 1809	November 13, 2018
18362	Windows 10, Version 1903	May 21, 2019
18363	Windows 10, Version 1909	November 12, 2019
19041	Windows 10, Version 2004	May 27, 2020
19042	Windows 10, Version 20H2	October 20, 2020
19043	Windows 10, Version 21H1	May 18, 2021
19044	Windows 10, Version 21H2	November 16, 2021
20348	Windows Server 2022, Version 21H2	August 18, 2021
22000	Windows 11, Version 21H2	October 4, 2021
22610	Windows 11 Insider Preview	April 29, 2022
22621	Windows 11, Version 22H2	September 20, 2022
25115	Windows 11 Insider Preview	May 11, 2022
25145	Windows 11 Insider Preview	June 22, 2022
25163	Windows 11 Insider Preview	July 20, 2022

Infection Chain

It is important to note that the threat actor used MSI and EXE files in their previous campaign. While the most recent version was based on JavaScript files named as follows:-

• SYSTEM.Critical.Upgrade.Win10.0.ba45bd8ee89b1.js
• SYSTEM.Security.Database.Upgrade.Win10.0.jse
• Antivirus_Upgrade_Cloud.29229c7696d2d84.jse
• ALERT.System.Software.Upgrade.392fdad9ebab262cc97f832c40e6ad2c.js

The files that are used in this attack are obfuscated and they execute a .NET file in system memory using a variation of the “DotNetToJScript” technique. Consequently, the host’s anti-virus products are less likely to detect this attack.

Before terminating its own process, the .NET file injects the shellcode it decodes into a new script that makes stealthy syscalls using its own wrapper.

Using a bypass for the Windows User Account Control feature, Magniber can take advantage of this option to perform this action. In order to perform this, a registry key has to be created to allow the user to specify the shell command that should be executed. 

Then a VBScript script is executed later in the process to delete the shadow copies as is the “fodhelper.exe” utility in a subsequent step.

Once everything is in place, the Magniber ransomware starts encrypting the files, and then it drops the ransom note on the host. However, it has been found that Magniber encrypts specific file types only.

Recommendation

Here below we have mentioned all the recommendations:-

• Make use of administrator accounts only when you need them.
• The most reliable way to update your software is to download it from an authoritative source.
• Make sure you are backing up your data on a regular basis.

Also Read: Ransomware Attack Response and Mitigation Checklist