SASE Week 2023 On-Demand! Explore sessions.

  • Security Service Edge Products

    Protect against advanced and cloud-enabled threats and safeguard data across all vectors.

  • Borderless SD-WAN

    Confidently provide secure, high-performance access to every remote user, device, site, and cloud.

The platform of the future is Netskope

Intelligent Security Service Edge (SSE), Cloud Access Security Broker (CASB), Cloud Firewall, Next Generation Secure Web Gateway (SWG), and Private Access for ZTNA built natively into a single solution to help every business on its journey to Secure Access Service Edge (SASE) architecture.

Go to Products Overview
Netskope video
Borderless SD-WAN: Ushering in the New Era of Borderless Enterprise

Netskope Borderless SD-WAN offers an architecture that converges zero trust principles and assured application performance to provide unprecedented secure, high-performance connectivity for every site, cloud, remote user, and IoT device.

Read the article
Borderless SD-WAN
  • NewEdge

    NewEdge is the world’s largest, highest-performing security private cloud.

  • Cloud Security Platform

    Unrivaled visibility and real-time data and threat protection on the world's largest security private cloud.

  • Technology Partners & Integrations

    Netskope partners with the strongest companies in enterprise technology.

Embrace a Secure Access Service Edge (SASE) architecture

Netskope NewEdge is the world’s largest, highest-performing security private cloud and provides customers with unparalleled service coverage, performance and resilience.

Learn about NewEdge
Your Network of Tomorrow

Plan your path toward a faster, more secure, and more resilient network designed for the applications and users that you support.

Get the white paper
Your Network of Tomorrow
Netskope Cloud Exchange

The Netskope Cloud Exchange (CE) provides customers with powerful integration tools to leverage investments across their security posture.

Learn about Cloud Exchange
Netskope video
Make the move to market-leading cloud security services with minimal latency and high reliability.

Learn about NewEdge
Lighted highway through mountainside switchbacks
Safely enable the use of generative AI applications with application access control, real-time user coaching, and best-in-class data protection.

Learn how we secure generative AI use
Safely Enable ChatGPT and Generative AI
Zero trust solutions for SSE and SASE deployments

Learn about Zero Trust
Boat driving through open sea
Netskope enables a safe, cloud-smart, and fast journey to adopt cloud services, apps, and public cloud infrastructure.

Learn about Industry Solutions
Wind turbines along cliffside
  • Resources

    Learn more about how Netskope can help you secure your journey to the cloud.

  • Blog

    Learn how Netskope enables security and networking transformation through security service edge (SSE).

  • Events & Workshops

    Stay ahead of the latest security trends and connect with your peers.

  • Security Defined

    Everything you need to know in our cybersecurity encyclopedia.

Security Visionaries Podcast

Unveiling the Under-reported Aspects of AI
Emily Wearmouth sits down with Neil Thacker, EMEA CISO, Yihua Liao, Head of Netskope AI Labs, and Suzanne Oliver, Director of IP Strategy at Scintilla, to discuss the topics in the realm of AI that they each wish people were discussing more.

Play the podcast
Unveiling the Under-reported Aspects of AI Social card
Latest Blogs

How Netskope can enable the Zero Trust and SASE journey through security service edge (SSE) capabilities.

Read the blog
Sunrise and cloudy sky
SASE Week 2023: Your SASE journey starts now!

Replay sessions from the fourth annual SASE Week.

Explore sessions
SASE Week 2023
What is Security Service Edge?

Explore the security side of SASE, the future of network and protection in the cloud.

Learn about Security Service Edge
Four-way roundabout
  • Our Customers

    Netskope serves more than 2,000 customers worldwide including more than 25 of the Fortune 100

  • Customer Solutions

    We are here for you and with you every step of the way, ensuring your success with Netskope.

  • Netskope Community

    Learn from other network, data, and security professionals.

  • Training and Certification

    Netskope training will help you become a cloud security expert.

We help our customers to be Ready for Anything

See our Customers
Woman smiling with glasses looking out window
Netskope’s talented and experienced Professional Services team provides a prescriptive approach to your successful implementation.

Learn about Professional Services
Netskope Professional Services
The Netskope Community can help you and your team get more value out of products and practices.

Go to the Netskope Community
The Netskope Community
Secure your digital transformation journey and make the most of your cloud, web, and private applications with Netskope training.

Learn about Training and Certifications
Group of young professionals working
  • Company

    We help you stay ahead of cloud, data, and network security challenges.

  • Why Netskope

    Cloud transformation and work from anywhere have changed how security needs to work.

  • Leadership

    Our leadership team is fiercely committed to doing everything it takes to make our customers successful.

  • Partners

    We partner with security leaders to help you secure your journey to the cloud.

Supporting sustainability through data security

Netskope is proud to participate in Vision 2045: an initiative aimed to raise awareness on private industry’s role in sustainability.

Find out more
Supporting Sustainability Through Data Security
Highest in Execution. Furthest in Vision.

Netskope recognized as a Leader in the 2023 Gartner® Magic Quadrant™ for Security Service Edge.

Get the report
Netskope recognized as a Leader in the 2023 Gartner® Magic Quadrant™ for Security Service Edge.
Thinkers, builders, dreamers, innovators. Together, we deliver cutting-edge cloud security solutions to help our customers protect their data and people.

Meet our team
Group of hikers scaling a snowy mountain
Netskope’s partner-centric go-to-market strategy enables our partners to maximize their growth and profitability while transforming enterprise security.

Learn about Netskope Partners
Group of diverse young professionals smiling

Netskope Threat Coverage: BlackMatter

Aug 23 2021


In July of 2021, a new ransomware named BlackMatter emerged and was being advertised in web forums where the group was searching for compromised networks from companies with revenues of $100 million or more per year. Although they are not advertising as a Ransomware-as-a-Service (RaaS), the fact they are looking for “partners” is an indication that they are operating in this model. Furthermore, the group is claiming to have combined features from larger groups, such as DarkSide and REvil (a.k.a. Sodinokibi).

Screenshot of BlackMatter advertisement in a web forum.
BlackMatter advertisement in a web forum. (Source: The Record)

According to an interview with an alleged representative from BlackMatter, they have incorporated the ideas of LockBit, REvil, and DarkSide, after studying their ransomware in detail. Also, the BlackMatter representative believes that other ransomware groups have disappeared from the scene due to attention from governments following high-profile attacks.  BlackMatter plans to avoid such attention by being careful not to infect any critical infrastructure. This is echoed on their website, which states they are not willing to attack hospitals, critical infrastructures, defense industry, and non-profit companies.

Screenshot of Main page of BlackMatter’s website, hosted on the deep web.
Main page of BlackMatter’s website, hosted on the deep web.

The oil and gas industry is also excluded from the target list, a reference to the Colonial Pipeline attack where DarkSide stopped the fuel delivery across the Southeastern of the United States, followed by the shut down of the ransomware operation due to the pressure from law enforcement. The BlackMatter spokesperson also said that the Colonial PIpeline attack was a key factor for the shutdown of REvil and DarkSide, and that’s why they are excluding this kind of sector from the target list.

BlackMatter already claims to have hit three victims, each listed on their deep web site, which follows the same standard from other groups, containing the name of the attacked company, a summary of what data they have stolen, and the deadline for the ransom before the data is published.

Screenshot showing one of the DarkSide targets, with leaked data on the website.
One of the DarkSide targets, with leaked data on the website.

One of the companies infected by BlackMatter is SolarBR, which is the second-largest manufacturer of Coca-Cola in Brazil, where the group claimed to have stolen 50 GB of confidential finance, logistics, development, and other data.

Screenshot showing that Solar Coca-Cola was infected by BlackMatter
Solar Coca-Cola infected by BlackMatter

According to the post, if the ransom isn’t paid, the group will publish the data and inform all of the “biggest mass-media in Brazil and US,” making “Coca Cola and her lovers” to be “madly angry”.

Screenshot of additional information from BlackMatter’s deep web site.
Information from BlackMatter’s deep web site.

There is no official information about the ransom amount BlackMatter is requesting from Solar Coca-Cola, but the deadline is set to August 23, 2021.

In this threat coverage report, we will analyze a Windows BlackMatter sample, version 1.2, describing some of the key features of the malware. 


Like other malware, BlackMatter implements many techniques to avoid detection and make reverse engineering more challenging. The first item we would like to cover is how BlackMatter dynamically resolves API calls to hide them from the PE import table.

This is done by a multi-step process. First, the malware creates a unique hash that will identify both the DLL and API name that needs to be executed. To make this a bit harder for static detections, the real hash value is encrypted with a simple XOR operation. In this case, the key is 0x22065FED.

Figure showing function that loads the import based on a hash.
Figure 1. Function that loads the import based on a hash.

In the example above, after the XOR operation, the value 0x27D05EB2 is passed as a parameter to the function responsible for searching and loading the API. The code first enumerates all the DLLs that are loaded within the process through a common but interesting technique. 

First, it loads the Process Environment Block (PEB) address, which is located in the Thread Environment Block (TEB). Then, it loads the doubly linked list that contains all the loaded modules for the process, located in the PEB_LDR_DATA structure.

Figure showing BlackMatter function searching loaded modules using the PEB.
Figure 2. BlackMatter function searching loaded modules using the PEB.

Once the loaded DLL is located, the function retrieves the DLL’s offset, finds the PE header address, and then calculates the offset of the PE export directory, so it can enumerate the APIs exported by the DLL.

If the export table is found, the ransomware then calculates the hash value for both DLL and API name, using the following function:

Figure showing the function used by BlackMatter to calculate the hash of the string.
Figure 3. Function used by BlackMatter to calculate the hash of the string.

To get the unique hash, the ransomware first calculates the hash only for the DLL name.

Figure showing hash generation for the DLL “kernel32.dll”
Figure 4. Hash generation for the DLL “kernel32.dll”

In the example above, the hash for the DLL “kernel32.dll” is 0xB1FC7F66, which is then used by this same function to calculate the hash of the API name.

Figure generating the final hash for DLL + API name
Figure 5. Generating the final hash for DLL + API name

Therefore, using the same function again, the malware has generated the hash 0x27D05EB2 for the DLL “kernel32.dll” and the API “LoadLibraryA”, which is exactly the same value the malware is seeking, as demonstrated in Figure 1.

If the hash generated by the function matches the hash the malware passed as a parameter, the offset for the API is stored in memory, so the function can be called.

Figure showing BlackMatter’s code before and after the APIs were dynamically resolved.
Figure 6. BlackMatter’s code before and after the APIs were dynamically resolved.

Several DLLs are loaded by BlackMatter dynamically after the executable is running, as we can see below.

Figure showing DLLs dynamically loaded by BlackMatter.
Figure 7. DLLs dynamically loaded by BlackMatter.

To make the analysis faster, we’ve created a script that implements the same logic used by BlackMatter for the hash generation. Therefore, the script can be used to locate calls to specific APIs across BlackMatter’s code.

Figure showing script to generate the hash based on the API call.
Figure 8. Script to generate the hash based on the API call.

Another technique used by BlackMatter to stay under the radar is to encrypt all its important strings. In the samples we’ve analyzed, the ransomware used the same key as the one used to generate the hashes for the API loading process.

Figure showing BlackMatter’s routine for string decryption.
Figure 9. BlackMatter’s routine for string decryption.

After the bytes are organized in memory, the code decrypts the data in 4-byte blocks, using a simple XOR operation with the key 0x22065FED.

Figure showing example of a string decrypted by BlackMatter.
Figure 10. Example of a string decrypted by BlackMatter.

We can find useful information across the decrypted strings, such as registry keys, file names, and others. The full list of decrypted strings can be found in our GitHub repository.

Figure showing some of BlackMatter’s decrypted strings.
Figure 11. Some of BlackMatter’s decrypted strings.

BlackMatter also has an encrypted configuration inside the binary, located in a fake PE resource section.

Figure showing BlackMatter’s encrypted configuration.
Figure 12. BlackMatter’s encrypted configuration.

The first 4 bytes in the section are the initial decryption key, the following 4 bytes represent the size of the data, and the rest of the bytes are the encrypted configuration. The data is then decrypted using a rolling XOR algorithm.

A new decryption key is generated every 4 bytes, using a dynamic seed and a constant, which is 0x8088405 in all the samples we have analyzed so far.

Figure showing the stub that generates the decryption key.
Figure 13. Stub that generates the decryption key.

The decrypted configuration is compressed using aPLib, so we need to decompress the bytes to get the information. Once this process is done, we can read the contents of the configuration. At the beginning, we can find the attacker’s RSA public key, the AES key used to encrypt C2 communication, as well as a 16-byte value named “bot_company”.

Figure showing BlackMatter’s decrypted configuration.
Figure 14. BlackMatter’s decrypted configuration.

Aside from that, the configuration also includes several base64 encoded strings that contain sensitive strings used by the malware, like the C2 server addresses.

Figure decoding BlackMatter’s C2 server addresses.
Figure 15. Decoding BlackMatter’s C2 server addresses.

Among the strings, there is also a list of processes and services that the ransomware attempts to stop \ terminate.

Figure showing ransomware trying to open the VSS service.
Figure 16. Ransomware trying to open the VSS service.

To speed up the analysis, we have created a script that is able to decrypt the strings and the configuration from BlackMatter samples.

Figure decrypting BlackMatter’s strings.
Figure 17. Decrypting BlackMatter’s strings.

The script also decodes all base64 values from the configuration automatically:

Figure showing BlackMatter’s C2 server addresses.
Figure 18. BlackMatter’s C2 server addresses.

BlackMatter communicates with the C2 server in order to send information to the attackers. It first loads a JSON structure in memory, containing all the information that will be sent.

Figure showing information that will be sent to the C2 address.
Figure 19. Information that will be sent to the C2 address.

Prior to the POST request, the information is encrypted using AES-128 ECB, with the key extracted from the configuration, and then encoded with base64.

Figure showing BlackMatter sending request to the C2 server.
Figure 20. BlackMatter sending request to the C2 server.

It’s possible to decrypt this information by decoding the base64 and decrypting the data using the key from the configuration file.

Figure decrypting BlackMatter’s C2 request.
Figure 21. Decrypting BlackMatter’s C2 request.

BlackMatter sends two requests, the first one contains details about the infected environment, and the second one contains details about the encryption process, such as how many files failed to encrypt, the start and end time, etc.

Finally, once the encryption process is complete, the ransom note is created in the same places where there are encrypted files.

Figure showing BlackMatter’s ransom note.
Figure 22. BlackMatter’s ransom note.

BlackMatter changes the background image, a common practice among ransomware creators.

Figure showing BlackMatter’s custom background
Figure 23. BlackMatter’s custom background


Netskope Threat Labs is actively monitoring this campaign and has ensured coverage for all known threat indicators and payloads. 

  • Netskope Threat Protection
    • Trojan.GenericKD.46740173
    • Gen:Heur.Mint.Zard.25
  • Netskope Advanced Threat Protection provides proactive coverage against this threat.
    • Gen.Malware.Detect.By.StHeur indicates a sample that was detected using static analysis
    • Gen.Malware.Detect.By.Sandbox indicates a sample that was detected by our cloud sandbox







A full list of IOCs, a Yara rule, and the scripts used in the analysis are all available in our Git repo.

author image
Gustavo Palazolo
Gustavo Palazolo is an expert in malware analysis, reverse engineering and security research, working many years in projects related to electronic fraud protection. He is currently working on the Netskope Research Team, discovering and analyzing new malware threats.

Stay informed!

Subscribe for the latest from the Netskope Blog