Threat Assessment: Matrix Ransomware

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Executive Summary

Matrix is a ransomware family that was first identified publicly in December 2016. Over the years since its inception, it has primarily targeted small- to medium-sized organizations. As of 2019, it had been observed across geographic locations such as the U.S., Belgium, Taiwan, Singapore, Germany, Brazil, Chile, South Africa, Canada and the UK. While initially leveraging tactics such as spam email campaigns, propagation via Windows shortcuts and the RIG exploit kit for distribution, the primary attack vector for the Matrix ransomware family shifted in 2018 to brute forcing weak Remote Desktop Protocol (RDP) credentials. The shift to this attack methodology appears to be a recurring trend in similar targeted ransomware families such as Dharma, Ryuk and BitPaymer.

Matrix Ransomware Overview

When executed, Matrix encrypts user files and network shares, as well as deleting volume shadow copies and disabling recovery options on the affected device. Like with many other ransomware variants, the ransom note delivered by Matrix demands payment in Bitcoin. Instead of spreading through an organization, past Matrix infections appear to have been more targeted in nature.

Matrix is unique in that instead of delivering a more conventional ransom note that demands a fixed ransom amount, the threat actors behind it ask victims to contact them directly and submit a small sample of about three to five files for decryption. This is done so the threat actors can determine a variable ransom based on factors such as the predicted value of the victim’s files or the current dollar value of Bitcoin.

As of 2020, Matrix ransomware has been seen appending the following file extensions on files:
.MTXLOCK, .CORE, .ANN, .FOX, .KOK8, .KOK08, .NEWRAR, .FASTBOB, .FASTB, .EMAN, .THDA, .RAD, .EMAN50, .GMPF, .ATOM, .NOBAD, .TRU8, .FASTA, .JNSS, .FBK, .ITLOCK, .SPCT, .PRCP, .CHRB, .AL8G, .DEUS, .FG69, .JB88, .J91D, .S996, .[barboza40@yahoo.com], .[Linersmik@naver.com][Jinnyg@tutanota.com], .[poluz@tutanota.com], .[Yourencrypt@tutanota.com], .[Files4463@tuta.io], .[RestorFile@tutanota.com], .[RestoreFile@qq.com], .[oken@tutanota.com], .[Vfemacry@mail-on.us], .[d3336666@tutanota.com], and .[Bitmine8@tutanota.com]

In addition, Matrix has other variants, including one dubbed “Fox Ransomware,” which adds the “.FOX” extension to encrypted files.

More information on prominent ransomware families can be found in the 2021 Unit 42 Ransomware Threat Report.

Courses of Action

This section documents relevant tactics, techniques and procedures (TTPs) used with Matrix and maps them directly to Palo Alto Networks product(s) and service(s). It also further instructs customers on how to ensure their devices are configured correctly.

^{Table 1. Courses of Action for Matrix ransomware.
†These capabilities are part of the NGFW security subscriptions service.}

Conclusion

While targeted ransomware attacks are not new, Matrix is a prime example of how threat actors can enter into the pool of existing ransomware and cash out quickly by targeting low-hanging fruit. The ransom negotiation tactics used by the Matrix threat actors further amplifyies the dangerous impact that such an attack can have on its victims, especially given the volatile state of cryptocurrency value today. Furthermore, this malware family’s shift in tactics to RDP exploitation, following a similar shift seen in other ransomware groups, serves to emphasize the need for businesses to stay vigilant on current ransomware trends.

Palo Alto Networks detects and prevents Matrix in the following ways:

• WildFire: All known samples are identified as malware.
• Cortex XDR with:
  • Iindicators for Matrix.
  • Anti-Ransomware Module to detect Matrix encryption behaviors.
  • Local Analysis detection to detect Matrix binaries.
• Next-Generation Firewalls: DNS Signatures detect the known command and control (C2) domains, which are also categorized as malware in URL Filtering.
• AutoFocus: Tracking related activity using the MatrixRansomware tag.

Additionally, Indicators of Compromise (IoCs) associated with Matrix are available on GitHub here, and have been published to the Unit 42 TAXII feed.

Additional Resources

• Matrix Ransomware Spreads to Other PCs Using Malicious Shortcuts
• Matrix has slowly evolved into a 'Swiss Army knife' of the ransomware world
• Matrix Ransomware Changes the Rules Again | How Much Are You Worth?