Evilnum Malware

By Ashwin Venugopal -

 





About Evilnum

The Evilnum malware mainly targets FinTech companies and it has been operating since 2018. However, very little have been published about the operating group behind this malware and its functioning. 

Its toolset and infrastructure have been considerably evolved with time, and now consists of a mixture of customized and homemade malware with combination of the tools purchased from Golden Chickens, which is a Malware-as-a-Service (MaaS) provider having many infamous customers like FIN6 and Cobalt Group. 

How does it works?

This APT group is using updated tactics, techniques, and procedures to target their victims. Previously, this threat group used Windows Shortcut files (LNK) sent inside malicious files (ZIP) as email attachments in spear phishing emails to the victims. Recently, they have started using MS Office Word documents, leveraging document template injection to deliver the malicious payload in a system. 

Several undetected domains associated with Evilnum have been discovered, indicating that this threat group has been successfully doing its activities under the radar and remained undetected for a very long time. 

Main Points

  • Evilnum has been mainly targeting FinTech (Financial Services) companies dealing with trading and compliance across UK and Europe. 

  • They are also targeting Intergovernmental organizations that deals with International Migration Services. 

  • The attack timeline and nature of choosing targets directly coincide with the Russia-Ukraine conflict.

  • Before, they used a heavily obfuscated JavaScript to decrypt and drop the payloads on the endpoints. This JavaScript configured a scheduled task to run the dropped binary. Now, this obfuscation technique has significant improvements as compared to the previous versions Evilnum.

  • Evilnum carefully chooses the names of all the file system artifacts created during the execution in order to spoof the legitimate Windows as well as the names of the other legitimate third parties.

  • The threat group registers multiple domain names, for every new campaign, via specific keywords related to the targeted industry. 

Prevention

Although Evilnum is very much capable of going undetected for years before causing destruction in an organization's system, there are certain ways to ensure safety against it, they are:

  • Make use of the many antivirus software available to protect and mitigate the attacks of threat actors like Evilnum.

  • Have a good cyber incident plan, that has been already tested via tabletop exercises.

  • Always review the security plan and regularly update it after it is tested on real cyber threats.

  • An organization must have a detailed defense strategy according to the risk analysis approach.

  • Educate the employees regarding cybersecurity and the potential dangers of opening malicious documents. Use annual or quarterly training modules to prevent threat actors from tricking employees into opening malicious email attachments. 


















































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