Malware Spotlight: RansomHub Ransomware

Report

Malware Spotlight: RansomHub Ransomware

Jan 8, 2025

Arete Analysis

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Executive Summary

In 2024, Arete’s Incident Response (IR) team responded to dozens of incidents attributed to the RansomHub threat actor group. Engagements attributed to RansomHub increased rapidly since Arete first observed them in May 2024, and the group quickly established itself as one of the top three threat actor groups since
July 2024.

RansomHub has impacted multiple sectors across Arete engagements, including professional services, public services, healthcare, high technology, financial services, and manufacturing. The group has targeted several high-profile targets since its emergence, including telecom giant Frontier and British auction house Christie’s. RansomHub also claimed to possess data stolen from Change Healthcare, which was the victim of an ALPHV/BlackCat ransomware attack in February 2024. RansomHub announced the sale of Change’s data after leaking some of the alleged data a day beforehand.

Advertisements for the RansomHub Ransomware-as-a-Service (RaaS) appeared on cybercriminal forums on February 2, 2024, highlighting an encryptor developed using the C++ and Go programming languages. The use of Go makes it easier for ransomware groups to target a wide variety of operating systems without needing to rewrite significant portions of the malware, as Go allows developers to compile executables for Windows, Linux, and macOS platforms from a single codebase. These advertisements were accompanied by
a new data leak site (DLS) under the RansomHub branding on the dark web.

RansomHub is suspected to be a re-brand of the “Knight” ransomware group, whose source code was listed for sale on the underground RAMP forum on February 18, 2024. From research, Arete can confirm various similarities between RansomHub and Knight’s encryptors.

This spotlight explores the ransomware group’s observed behavior, background information on the threat actor, and statistics from Incident Response engagements, along with a technical analysis of RansomHub’s ransomware executable. Finally, we discuss security recommendations to better defend against this evolving cyber threat and mitigate the risk of financial and reputational losses.

Incident Response Data on the RansomHub Ransomware Group

The information provided below is based on engagements involving the RansomHub threat actor group 
investigated by Arete in 2024. Our IR, Threat Intelligence, and Data Analytics teams work together 
to analyze key data points during every ransomware engagement and form real-time 
threat actor (TA) insights.
- Targeted sectors include professional services, public services, healthcare, high technology, 
  financial services, and manufacturing.
- The median initial ransom demand is $900,000.
- The median ransom payment facilitated is $350,000.
- Tools and malware observed during investigations include SocGholish, CobaltStrike, Mimikatz, 
  Rclone, Filezilla, WinSCP, PsExec, AnyDesk, PuTTY, WinSCP, Rclone, SoftPerfect Network Scanner, 
  and TDSSKiller and EDRKillShifter to disable EDR software to evade detection.
- RansomHub-affiliated actors have exploited vulnerabilities in a variety of technologies, 
  including Apache ActiveMQ, Atlassian Confluence, Citrix ADC, F5 BIG-IP, and Fortinet FortiOS.
- The group operates a data leak site (DLS) self-proclaimed as “RansomHub” and commonly threatens 
  victims with releasing stolen data as a pressure tactic if a payment is not made.
- The file extension appended to encrypted files is created based on the first six characters of 
  the Curve 25519 public key, and files are encrypted using a decrypted Curve 25519 public key and 
  AES algorithms.
- The ransom note created self-identifies the group as RansomHub and references their data leak 
  and chat negotiation sites. The filename of the ransom note is dependent on the encrypted file 
  extension as a naming convention and follows this format: “README_.txt”. For example: README_11f5ew.txt.
- In addition to encrypting files and creating a ransom note, the RansomHub ransomware needs a 
  password to properly execute, supports various command line arguments, deletes volume shadow 
  copies, clears the Windows Event Logs, and tries to stop virtual machines (VMs)

The information provided below is based on engagements involving the RansomHub threat actor group 
investigated by Arete in 2024. Our IR, Threat Intelligence, and Data Analytics teams work together 
to analyze key data points during every ransomware engagement and form real-time 
threat actor (TA) insights.
- Targeted sectors include professional services, public services, healthcare, high technology, 
  financial services, and manufacturing.
- The median initial ransom demand is $900,000.
- The median ransom payment facilitated is $350,000.
- Tools and malware observed during investigations include SocGholish, CobaltStrike, Mimikatz, 
  Rclone, Filezilla, WinSCP, PsExec, AnyDesk, PuTTY, WinSCP, Rclone, SoftPerfect Network Scanner, 
  and TDSSKiller and EDRKillShifter to disable EDR software to evade detection.
- RansomHub-affiliated actors have exploited vulnerabilities in a variety of technologies, 
  including Apache ActiveMQ, Atlassian Confluence, Citrix ADC, F5 BIG-IP, and Fortinet FortiOS.
- The group operates a data leak site (DLS) self-proclaimed as “RansomHub” and commonly threatens 
  victims with releasing stolen data as a pressure tactic if a payment is not made.
- The file extension appended to encrypted files is created based on the first six characters of 
  the Curve 25519 public key, and files are encrypted using a decrypted Curve 25519 public key and 
  AES algorithms.
- The ransom note created self-identifies the group as RansomHub and references their data leak 
  and chat negotiation sites. The filename of the ransom note is dependent on the encrypted file 
  extension as a naming convention and follows this format: “README_.txt”. For example: README_11f5ew.txt.
- In addition to encrypting files and creating a ransom note, the RansomHub ransomware needs a 
  password to properly execute, supports various command line arguments, deletes volume shadow 
  copies, clears the Windows Event Logs, and tries to stop virtual machines (VMs)

The information provided below is based on engagements involving the RansomHub threat actor group 
investigated by Arete in 2024. Our IR, Threat Intelligence, and Data Analytics teams work together 
to analyze key data points during every ransomware engagement and form real-time 
threat actor (TA) insights.
- Targeted sectors include professional services, public services, healthcare, high technology, 
  financial services, and manufacturing.
- The median initial ransom demand is $900,000.
- The median ransom payment facilitated is $350,000.
- Tools and malware observed during investigations include SocGholish, CobaltStrike, Mimikatz, 
  Rclone, Filezilla, WinSCP, PsExec, AnyDesk, PuTTY, WinSCP, Rclone, SoftPerfect Network Scanner, 
  and TDSSKiller and EDRKillShifter to disable EDR software to evade detection.
- RansomHub-affiliated actors have exploited vulnerabilities in a variety of technologies, 
  including Apache ActiveMQ, Atlassian Confluence, Citrix ADC, F5 BIG-IP, and Fortinet FortiOS.
- The group operates a data leak site (DLS) self-proclaimed as “RansomHub” and commonly threatens 
  victims with releasing stolen data as a pressure tactic if a payment is not made.
- The file extension appended to encrypted files is created based on the first six characters of 
  the Curve 25519 public key, and files are encrypted using a decrypted Curve 25519 public key and 
  AES algorithms.
- The ransom note created self-identifies the group as RansomHub and references their data leak 
  and chat negotiation sites. The filename of the ransom note is dependent on the encrypted file 
  extension as a naming convention and follows this format: “README_.txt”. For example: README_11f5ew.txt.
- In addition to encrypting files and creating a ransom note, the RansomHub ransomware needs a 
  password to properly execute, supports various command line arguments, deletes volume shadow 
  copies, clears the Windows Event Logs, and tries to stop virtual machines (VMs)

Background

RansomHub became a notable ransomware operation in 2024, and, alongside Akira, represented a verysignificant percentage of Arete Incident Response engagements in Q3 of 2024.

Source: Arete's Q3 2024 Crimeware Report

The group utilizes both Windows and Linux variants of encryptors, which increases its operational capability to target a wide range of victims of various sectors and sizes. RansomHub operates under a double extortion model, which involves exfiltrating sensitive data and encrypting the victims’ systems to coerce a payment for
a decryptor and data deletion.

Technical Analysis

Malware analysis revealed that RansomHub ransomware:

Supports multiple command-line arguments.
Requires a password to properly execute and encrypt files.
Encrypts files on the system and mounted shares.
Creates a ransom note with the following filename: .README_.txt
Self-identifies the group as RansomHub in the ransom note.
References a data leak site in the ransom note that, when accessed, self-identifies the group as RansomHub.
Kills a list of processes and services.
Maintains a list of whitelisted files and directories to make sure it will not render the system unusable, preventing recovery when running a decryptor.
Attempts to prevent system recovery by deleting the system’s volume shadow copies.
Clears the Windows event logs.
Creates a desktop wallpaper image in the “%temp%\” directory and later modifies a registry key to change desktop wallpaper.

Execution Pattern/Arguments

The RansomHub ransomware needs command line arguments to execute and encrypt files in the system.

Command line arguments supported:

Command line arguments	Description
-cmd	CMD to be executed before encryption.
-disable-net	Disable network before running.
-fast value	Fast encryption mode.
-file value	Only process file inside defined files. For example, -file C://1.txt, -file D://2.txt.
-host value	Only process net share inside defined hosts. -host 10.10.10.10 -host 10.10.10.11.
-only-local	Only encrypt local disks.
-pass [SHA256 string]	Password needed to execute the ransomware. A 64-character string.
-path value	Only process files inside defined paths. -path C:// -path D:// -path //10.10.10.10/d/
-safeboot	Reboot in Safe Mode before running.
-safeboot-instance	Run as Safe Mode instance.
-skip-vm value	Skip shutting down VMs. Example: -skip-vm “Ubuntu 22.04 LTS”, -skip-vm “Windows Server 2012”.
-sleep [integer value]	Sleep for a period of time to run (minute).
-verbose	Log to console.

Ransomware execution with the command line argument –help:

Figure 1. Command line arguments supported by the ransomware

The ransomware will not execute in the system without the “-pass” argument followed by a SHA-256 value that is unique in each engagement. Execution of ransomware to encrypt files:

RansomHub.exe -pass [SHA-256]

Example:
RansomHub.exe -pass

7ac8cd689f5d9f4c1ddca14ec84965ed42b17343ebe086076ba0e7a46a80f81f

Once the SHA-256 password value is provided, the ransomware will decrypt a JSON based ransomware configuration at the run time.

Decrypted JSON field name and descriptions:

Name	Description
master_public_key	Curve25519 public key used in the file encryption process.
extension	Extension added to encrypted files.
note_file_name	Ransom note file name, default value is .README<encrypted_file_extension>.txt
note_full_text	Ransom note content.
settings	Ransomware operation setting. Example: { “local_disks”: true, “network_shares”: true, “kill_processes”: true, “kill_services”: true, “set_wallpaper”: true, “net_spread”: true, “self_delete”: false, “running_one”: true }
credentials	Contains common or locally stolen credentials which are used for propagation and further infection.
kill_services	Terminates list of services.
kill_processes	Terminates list of processes.
white_folders	Excludes listed directories.
white_files	Excludes listed files.
white_hosts	Excludes listed hosts.

Stop Services and Processes

Before file encryption, the ransomware terminates a pre-determined list of processes and services to encrypt as many files as possible.

Process names:

“agntsvc.exe”, “dbeng50.exe”, “dbsnmp.exe”, “encsvc.exe”, “excel.exe”, “firefox.exe”, “infopath.exe”, “isqlplussvc.exe”, “msaccess.exe”, “mspub.exe”, “mydesktopqos.exe”, “mydesktopservice.exe”, “notepad.exe”, “ocautoupds.exe”, “ocomm.exe”, “ocssd.exe”, “onenote.exe”, “oracle.exe”, “outlook.exe”, “powerpnt.exe”, “sqbcoreservice.exe”, “sql.exe”, “steam.exe”, “synctime.exe”, “tbirdconfig.exe”, “thebat.exe”, “thunderbird.exe”, “visio.exe”, “winword.exe”, “wordpad.exe”, “xfssvccon.exe”, “sql.exe”, “bedbh.exe”, “vxmon.exe”, “benetns.exe”, “bengien.exe”, “pvlsvr.exe”, “beserver.exe”, “raw_agent_svc.exe”, “vsnapvss.exe”, “CagService.exe”, “QBIDPService.exe”, “QBDBMgrN.exe”, “QBCFMonitorService.exe”, “SAP.exe”, “TeamViewer_Service.exe”, “TeamViewer.exe”, “tv_w32.exe”, “tv_x64.exe”, “CVMountd.exe”, “cvd.exe”, “cvfwd.exe”, “CVODS.exe”, “saphostexec.exe”, “saposcol.exe”, “sapstartsrv.exe”, “avagent.exe”, “avscc.exe”, “DellSystemDetect.exe”, “EnterpriseClient.exe”, “VeeamNFSSvc.exe”, “VeeamTransportSvc.exe”, “VeeamDeploymentSvc.exe”

Services names:

“mepocs”, “memtas”, “veeam”, “svc$”, “backup”, “sql”, “vss”, “sql$”, “mysql”, “mysql$”, “sophos”, “MSExchange”, “MSExchange$”, “WSBExchange”, “PDVFSService”, “BackupExecVSSProvider”, “BackupExecAgentAccelerator”, “BackupExecAgentBrowser”, “BackupExecDiveciMediaService”, “BackupExecJobEngine”, “BackupExecManagementService”, “BackupExecRPCService”, “GxBlr”, “GxVss”, “GxClMgrS”, “GxCVD”, “GxCIMgr”, “GXMMM”, “GxVssHWProv”, “GxFWD”, “SAPService”, “SAP”, “SAP$”, “SAPD$”, “SAPHostControl”, “SAPHostExec”, “QBCFMonitorService”, “QBDBMgrN”, “QBIDPService”, “AcronisAgent”, “VeeamNFSSvc”, “VeeamDeploymentService”, “VeeamTransportSvc”, “MVArmor”, “MVarmor64”, “VSNAPVSS”, “AcrSch2Svc”

The ransomware also tries to list and stop VMs by executing the following PowerShell command.

powershell.exe -Command PowerShell -Command “{ Get-VM \| Stop-VM -Force }”
powershell.exe Get-VM \| Stop-VM -Force -inputFormat xml -outputFormat text

File and Directory Exclusions

The ransomware excludes system-related files and folders, ransomware-related files, and whitelisted extensions during encryption.

Excluded file and extensions:

“NTUSER.DAT”, “autorun.inf”, “boot.ini”, “desktop.ini”, “thumbs.db”, “.deskthemepack”, “.themepack”, “.theme”, “.msstyles”, “.exe”, “.drv”, “.msc”, “.dll”, “.lock”, “.sys”, “.msu”, “.lnk”, “.ps1”, “.iso”, “.inf”, “.cab”, “*.386”

Excluded directories:

“\\$windows.~ws”, “\\$windows.~bt”, “\\windows\\”, “\\windows.old”, “\\system volume information”, “\\Boot”, “\\PerfLogs”, “\\AppData\\Local\\Temp”, “\\AppData\\Local\\Microsoft\\GameDVR”, “\\ AppData\\Local\\Microsoft\\Edge”, “\\AppData\\Local\\Packages\\Microsoft.”, “\\AppData\\Local\\Packages\\ MicrosoftWindows.”, “\\AppData\\Local\\Packages\\Internet Explorer”, “\\Program Files\\Common Files\\microsoft shared”, “\\Program Files\\Common Files\\Services”, “\\Program Files\\Common Files\\System”, “\\Program Files\\Internet Explorer”, “\\Program Files\\ModifiableWindowsApps”, “\\Program Files\\Uninstall Information”, “\\Program Files\\Windows Defender”, “\\Program Files\\Windows Mail”, “\\Program Files\\Windows Media Player”, “\\Program Files\\Windows NT”, “\\Program Files\\Windows Photo Viewer”, “\\Program Files\\Windows Portable Devices”, “\\Program Files\\Windows Security”, “\\Program Files\\Windows Sidebar”, “\\Program Files\\ WindowsApps”, “\\Program Files\\WindowsPowerShell”, “\\Program Files (x86)\\Common Files”, “\\Program Files (x86)\\Common Files\\Microsoft Shared”, “\\Program Files (x86)\\Common Files\\Services”, “\\Program Files (x86)\\ Common Files\\System”, “\\Program Files (x86)\\Internet Explorer”, “\\Program Files (x86)\\Microsoft\\Edge”, “\\Program Files (x86)\\Microsoft\\Temp”, “\\Program Files (x86)\\Microsoft.NET”, “\\Program Files (x86)\\ Windows Defender”, “\\Program Files (x86)\\Windows Mail”, “\\Program Files (x86)\\Windows Media Player”, “\\Program Files (x86)\\Windows Multimedia Platform”, “\\Program Files (x86)\\Windows NT”, “\\Program Files (x86)\\Windows Photo Viewer”, “\\Program Files (x86)\\Windows Portable Devices”, “\\Program Files (x86)\\ Windows Security”, “\\Program Files (x86)\\Windows Sidebar”, “\\Program Files (x86)\\WindowsPowerShell”, “\\ ProgramData\\ssh\\”, “\\ProgramData\\USOPrivate”, “\\ProgramData\\USOShared”, “\\ProgramData\\Package Cache”, “\\ProgramData\\Microsoft\\Device Stage”, “\\ProgramData\\Microsoft\\DeviceSync”, “\\ProgramData\\ Microsoft\\Diagnosis”, “\\ProgramData\\Microsoft\\DiagnosticLogCSP”, “\\ProgramData\\Microsoft\\DRM”, “\\ ProgramData\\Microsoft\\UEV”, “\\ProgramData\\Microsoft\\EdgeUpdate”, “\\ProgramData\\Microsoft\\Event Viewer”, “\\ProgramData\\Microsoft\\IdentityCRL”, “\\ProgramData\\Microsoft\\MapData”, “\\ProgramData\\ Microsoft\\MF”, “\\ProgramData\\Microsoft\\NetFramework”, “\\ProgramData\\Microsoft\\Network”, “\\ ProgramData\\Microsoft\\Provisioning”, “\\ProgramData\\Microsoft\\Search”, “\\ProgramData\\Microsoft\\ SmsRouter”, “\\ProgramData\\Microsoft\\Spectrum”, “\\ProgramData\\Microsoft\\Speech_OneCore”, “\\ ProgramData\\Microsoft\\Storage Health”, “\\ProgramData\\Microsoft\\User Account Pictures”, “\\ProgramData\\ Microsoft\\Vault”, “\\ProgramData\\Microsoft\\WDF”, “\\ProgramData\\Microsoft\\Windows”, “\\ProgramData\\ Microsoft\\Windows Defender”, “\\ProgramData\\Microsoft\\Windows NT”, “\\ProgramData\\Microsoft\\ Windows Security Health”, “\\ProgramData\\Microsoft\\WinMSIPC”, “\\ProgramData\\Microsoft\\WPD”, “\\ ProgramData\\Packages\\USOPrivate”, “\\ProgramData\\Packages\\USOShared”, “\\ProgramData\\Packages\\ WindowsHolographicDevices”, “\\ProgramData\\Packages\\MicrosoftWindows.”, “\\ProgramData\\Packages\\ Microsoft.”

Inhibit System Recovery

Windows operating systems contain features that can help fix corrupted system files, including shadow copies, which are backups of files created by the Volume Shadow Copy Service (VSS). By deleting shadow copies, the ransomware can prevent victims from restoring files from backups, making it more difficult for them to recover their data without paying the ransom.

The ransomware deletes volume shadow copies before file encryption by starting the following process:

powershell.exe -Command PowerShell -Command “\”Get-CimInstance Win32_ShadowCopy \| Remove-CimInstance\””

System Network Connections Discovery

The ransomware can enumerate network-mounted shares by scanning the network interfaces.

Data Encrypted for Impact

The ransomware initially finds available drives, then loads the files one by one using the Windows API “FindFirstFileW“ and “FindNextFileW”. The ransomware generates random keys to encrypt the files, and after encrypting them, the keys are encrypted using a public key. To encrypt files, the ransomware uses a combination of a decrypted Curve 25519 public key and AES algorithms.

The default extension value is the first six characters of the Curve 25519 public key.

Figure 2. Extension added to the encrypted files

Files smaller than 0x100000 bytes are completely encrypted. If the file size is larger than 0x100000 bytes, the ransomware encrypts the file in 0x100000 bytes blocks and skips every 0x200000 bytes of data in between encrypted chunks.

Figure 3. 0x100000 bytes encrypted file.

Upon successful execution, the ransomware creates ransom notes with the file name “README_[encrypted_file_extension].txt”

Figure 4. RansomHub ransom note

Ransom note content:

We are the RansomHub.

Your company Servers are locked and Data has been taken to our servers. This is serious.

Good news:
– your server system and data will be restored by our Decryption Tool, we support trial decryption to prove that your files can be decrypted;
– for now, your data is secured and safely stored on our server;
– nobody in the world is aware about the data leak from your company except you and RansomHub team;
– we provide free trial decryption for files smaller than 1MB. If anyone claims they can decrypt our files, you can ask them to try to decrypt a file larger than 1MB.

FAQs:
Who we are?
– Normal Browser Links: https://ransomxifxwc5eteopdobynonjctkxxvap77yqifu2emfbecgbqdw6qd[.]onion.ly/
– Tor Browser Links: http://ransomxifxwc5eteopdobynonjctkxxvap77yqifu2emfbecgbqdw6qd[.]onion/

Want to go to authorities for protection?
– Seeking their help will only make the situation worse,They will try to prevent you from negotiating with us, because the negotiations will make them look incompetent,After the incident report is handed over to the government
department, you will be fined <This will be a huge amount,Read more about the GDRP legislation: https://en.wikipedia.org/wiki/General_Data_Protection_Regulation>, The government uses your fine to reward them.And you will not get anything, and except you and your company, the rest of the people will forget what happened!!!!!

Think you can handle it without us by decrypting your servers and data using some IT Solution from third-party “specialists”?
– they will only make significant damage to all of your data; every encrypted file will be corrupted forever. Only our Decryption Tool will make decryption guaranteed;

Don’t go to recovery companies, they are essentially just middlemen who will make money off you and cheat you.
– We are well aware of cases where recovery companies tell you that the ransom price is 5 million dollars, but in fact they secretly negotiate with us for 1 million dollars, so they earn 4 million dollars from you. If you approached us directly without intermediaries you would pay 5 times less, that is 1 million dollars.

Think your partner IT Recovery Company will do files restoration?
– no they will not do restoration, only take 3-4 weeks for nothing; besides all of your data is on our servers and we can publish it at any time; as well as send the info about the data breach from your company servers to your key partners and clients,
competitors, media and youtubers, etc. Those actions from our side towards your company will have irreversible negative consequences for your business
reputation.

You don’t care in any case, because you just don’t want to pay?
– We will make you business stop forever by using all of our experience to make your partners, clients, employees and whoever cooperates with your company change their minds by having no choice but to stay away from your company.
As a result, in midterm you will have to close your business.

So lets get straight to the point.

What do we offer in exchange on your payment:
– decryption and restoration of all your systems and data within 24 hours with guarantee;
– never inform anyone about the data breach out from your company;
– after data decryption and system restoration, we will delete all of your data from our servers forever;
– provide valuable advising on your company IT protection so no one can attack your again.

Now, in order to start negotiations, you need to do the following:
– install and run ‘Tor Browser’ from https://www.torproject.org/download/
– use ‘Tor Browser’ open <TA_URL_removed_by_analyst>.onion/
– enter your Client ID: <ID_removed_by_analyst>
* do not leak your ID or you will be banned and will never be able to decrypt your files.

There will be no bad news for your company after successful negotiations for both sides. But there will be plenty of those bad news if case of failed negotiations, so don’t think about how to avoid it. Just focus on negotiations, payment and decryption to make all of your problems solved by our specialists within 1
day after payment received: servers and data restored, everything will work good as new.

************************************************

Modify Registry

The ransomware performs a registry key modification to change the desktop wallpaper.

Registry key change:

Registry key	Value name	Value data
Computer\HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\ CurrentVersion\Explorer\Wallpapers	BackgroundHistory Path0	C:\Users\%USERNAME%\ AppData\Local\Temp\MkgXoB.png

Registry key

Value name

Value data

Computer\HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\

CurrentVersion\Explorer\Wallpapers

BackgroundHistory
Path0

C:\Users\%USERNAME%\
AppData\Local\Temp\MkgXoB.png

Screenshot showing the registry key modification:

Wallpaper image content from the
C:\Users\%USERNAME%\AppData\Local\Temp\MkgXoB.png file:

Mutex

The mutex is the fundamental tool for managing shared resources between multiple threads or processes. Typically, ransomware uses a mutex to avoid reinfecting the victim system and causing multiple layers of encryption. The ransomware did not create a mutex during execution.

Network Activity

The ransomware did not try to communicate with a remote server other than encrypting data from mounted shares.

Indicator Removal

The ransomware clears Windows Event Logs to hide its malicious activity. Windows Event Logs keep a record of a computer’s alerts and notifications. The ransomware runs the following commands to clear the logs:

cmd.exe /c wevtutil cl security cmd.exe /c wevtutil cl system cmd.exe /c wevtutil cl application

File and Directory Permissions Modification

The ransomware uses the fsutil tool to redirect file system access to a different location after gaining access to a compromised network. The ransomware uses the following command line to redirect file system access, enabling remote to remote and remote to local symbolic links:

fsutil behavior set SymlinkEvaluation R2L:1 fsutil behavior set SymlinkEvaluation R2R:1

Indicators of Compromise

Indicator	Type	Context
de7913504efe4584bdd9dd1ec13c4de4152a84df5e1cb-c31d0dd8fe70c88b5e0 4ac0e6c804f638182ee8e23c37e0c474a22f8bc2b3eed5ac-c0a56764839e4106 83654c500c68418142e43b31ebbec040d9d36cfbbe08c7b9b-3dc90fabc14801a eaee06cb53ff473f32d02ad1aca38957812b394f69dd0a3d2af-16f2d923b10e3	SHA256 hash	RansomHub ransomware
README_<encrypted_file_extension>.txt	File name	RansomHub ransom note
powershell.exe -Command PowerShell -Command “{ Get-VM \| Stop-VM -Force }”	Process	Retrieve information about VMs and forces a shutdown
powershell.exe -Command PowerShell -Command ” \\”Get-CimInstance Win32_ShadowCopy \| Remove-CimInstance\\”” cmd.exe /c “\\”vssadmin.exe Delete Shadows /all /quiet\\””	Process	Volume Shadow Copy deletion
cmd.exe /c wevtutil cl security cmd.exe /c wevtutil cl system cmd.exe /c wevtutil cl application	Process	Clearing Windows Event Logs
cmd.exe /c “\\”fsutil behavior set SymlinkEvaluation R2L:1\\”” cmd.exe /c “\\”fsutil behavior set SymlinkEvaluation R2R:1\\””	Process	Enable remote to remote and remote to local symbolic links
Key: Computer\HKEY_CURRENT_USER\SOFTWARE\Microsoft\ Windows\CurrentVersion\Explorer\Wallpapers Value: BackgroundHistoryPath0 Data: C:\Users\%USERNAME%\AppData\Local\Temp\MkgXoB. png	Registry	Desktop wallpaper modification
ransomxifxwc5eteopdobynonjctkxxvap77yqifu2emfbecgbqdw6qd[.] onion	URL	TA data leak site (DLS)

Ransomware Configuration

RansomHub decrypted configuration information extracted:

{"master_public_key": <public_key_removed_by_analyst> "extension": 
"<extension_removed_by_analyst>" "note_file_name": 
"README_<extension_removed_by_analyst>.txt", "note_full_text": "We are the RansomHub.
\n\nYour company Servers are locked and Data has been taken to our servers. This is serious. 
\n\nGood news:\n- your server system and data will be restored by our Decryption Tool, we supply 
trial decryption to prove that your files can be decrypted;\n- for now, your data is secured and
safely stored on our server;\n- nobody in the world is aware about the data leak from your company 
except you and RansomHub team;\n- we provide free trial decryption for files smaller than 1MB. If 
anyone claims they can decrypt our files, you can ask them to try to decrypt a file larger than 
1MB.\n\nFAQs:\nWho we are?\n- Normal Browser Links: https://ransomxifxwc5eteopdobynonjctkxvap77yqifu2emfbecbqdw6qd.onion.ly/\n- 
Tor Browser 
Links: 
http://ransomxifxwc5eteopdobynonjctkxvap77yqifu2emfbecbqdw6qd.onion/\n\nWant to go to authorities 
for protection?\n- Seeking their help will only make the situation worse,They will try to prevent 
you from negotiating with us, because the negotiations will make them look incompetent,After the 
incident report is handed over to the government department, you will be fined 
<This will be a huge amount,Read more about the GDRP legislation:https://
en.wikipedia.org/wiki/General_Data_Protection_Regulation> The government uses your fine to reward 
them.And you will not get anything, and except you and your company, the rest of the people will 
forget what happened!!!!!\n\nThink you can handle it without us by decrypting your servers and 
data using some IT Solution from third-party \"specialists\"?\n- they will only make significant 
damage to all of your data; every encrypted file will be corrupted forever. Only our Decryption 
Tool will make decryption guaranteed;\nDon't go to recovery companies, they are essentially just 
middlemen who will make money off you and cheat you. \n- We are well aware of cases where recovery 
companies tell you that the ransom price is 5 million dollars, but in fact they secretly negotiate 
with us for 1 million dollars, so they earn 4 million dollars from you. If you approached us 
directly without intermediaries you would pay 5 times less, that is 1 million dollars.\n\nThink 
your partner IT Recovery Company will do files restoration?\n- no they will not do restoration, 
only take 3-4 weeks for nothing; besides all of your data is on our server and we can publish it 
at any time; \n as well as send the info about the data breach from your company servers to your 
key partners and clients, competitors, media and youtubers, etc. \n Those actions from our side 
towards your company will have irreversible negative consequences for your business reputation.
\n\nYou don't care in any case, because you just don't want to pay? \n- We will make you business 
stop forever by using all of our experience to make your partners, clients, employees and whoever 
cooperates with your company change their minds by having no choice but to stay away from your 
company. \nAs a result, in midterm you will have to close your business. \n\nSo lets get straight 
to the point.\n\nWhat do we offer in exchange on your payment:\n- decryption and restoration of all 
your systems and data within 24 hours with guarantee;\n- never inform anyone about the data breach 
out from your company;\n- after data decryption and system restoration, we will delete all of your 
data from our servers forever;\n- provide valuable advising on your company IT protection so no 
one can hack you again.\n\nNow, in order to start negotiations, you need to do the following:\n- 
install and run 'Tor Browser' from https://www.torproject.org/download/\n- use 'Tor Browser' 
open <TA_URL_removed_by_analyst> \n- enter your ID or you will be banned and will never be able to 
decrypt your files.\n\nThere will be live chat for your company after successful negotiations for 
both sides. But there will be plenty of those bad cases of failed negotiations, so don't think about 
how to avoid it.\nJust focus on negotiations, payment and describe to make all of your problems 
solved by our specialists within 1 day after payment received: servers and data restored, 
everything will work good as new.\n\n************************************************\n",
"note_short_text": "Your data is stolen and encrypted, see README_<extension_removed_by_analyst>.txt.", "settings": 
  {"local_disks"

{"master_public_key": <public_key_removed_by_analyst> "extension": 
"<extension_removed_by_analyst>" "note_file_name": 
"README_<extension_removed_by_analyst>.txt", "note_full_text": "We are the RansomHub.
\n\nYour company Servers are locked and Data has been taken to our servers. This is serious. 
\n\nGood news:\n- your server system and data will be restored by our Decryption Tool, we supply 
trial decryption to prove that your files can be decrypted;\n- for now, your data is secured and
safely stored on our server;\n- nobody in the world is aware about the data leak from your company 
except you and RansomHub team;\n- we provide free trial decryption for files smaller than 1MB. If 
anyone claims they can decrypt our files, you can ask them to try to decrypt a file larger than 
1MB.\n\nFAQs:\nWho we are?\n- Normal Browser Links: https://ransomxifxwc5eteopdobynonjctkxvap77yqifu2emfbecbqdw6qd.onion.ly/\n- 
Tor Browser 
Links: 
http://ransomxifxwc5eteopdobynonjctkxvap77yqifu2emfbecbqdw6qd.onion/\n\nWant to go to authorities 
for protection?\n- Seeking their help will only make the situation worse,They will try to prevent 
you from negotiating with us, because the negotiations will make them look incompetent,After the 
incident report is handed over to the government department, you will be fined 
<This will be a huge amount,Read more about the GDRP legislation:https://
en.wikipedia.org/wiki/General_Data_Protection_Regulation> The government uses your fine to reward 
them.And you will not get anything, and except you and your company, the rest of the people will 
forget what happened!!!!!\n\nThink you can handle it without us by decrypting your servers and 
data using some IT Solution from third-party \"specialists\"?\n- they will only make significant 
damage to all of your data; every encrypted file will be corrupted forever. Only our Decryption 
Tool will make decryption guaranteed;\nDon't go to recovery companies, they are essentially just 
middlemen who will make money off you and cheat you. \n- We are well aware of cases where recovery 
companies tell you that the ransom price is 5 million dollars, but in fact they secretly negotiate 
with us for 1 million dollars, so they earn 4 million dollars from you. If you approached us 
directly without intermediaries you would pay 5 times less, that is 1 million dollars.\n\nThink 
your partner IT Recovery Company will do files restoration?\n- no they will not do restoration, 
only take 3-4 weeks for nothing; besides all of your data is on our server and we can publish it 
at any time; \n as well as send the info about the data breach from your company servers to your 
key partners and clients, competitors, media and youtubers, etc. \n Those actions from our side 
towards your company will have irreversible negative consequences for your business reputation.
\n\nYou don't care in any case, because you just don't want to pay? \n- We will make you business 
stop forever by using all of our experience to make your partners, clients, employees and whoever 
cooperates with your company change their minds by having no choice but to stay away from your 
company. \nAs a result, in midterm you will have to close your business. \n\nSo lets get straight 
to the point.\n\nWhat do we offer in exchange on your payment:\n- decryption and restoration of all 
your systems and data within 24 hours with guarantee;\n- never inform anyone about the data breach 
out from your company;\n- after data decryption and system restoration, we will delete all of your 
data from our servers forever;\n- provide valuable advising on your company IT protection so no 
one can hack you again.\n\nNow, in order to start negotiations, you need to do the following:\n- 
install and run 'Tor Browser' from https://www.torproject.org/download/\n- use 'Tor Browser' 
open <TA_URL_removed_by_analyst> \n- enter your ID or you will be banned and will never be able to 
decrypt your files.\n\nThere will be live chat for your company after successful negotiations for 
both sides. But there will be plenty of those bad cases of failed negotiations, so don't think about 
how to avoid it.\nJust focus on negotiations, payment and describe to make all of your problems 
solved by our specialists within 1 day after payment received: servers and data restored, 
everything will work good as new.\n\n************************************************\n",
"note_short_text": "Your data is stolen and encrypted, see README_<extension_removed_by_analyst>.txt.", "settings": 
  {"local_disks"

{"master_public_key": <public_key_removed_by_analyst> "extension": 
"<extension_removed_by_analyst>" "note_file_name": 
"README_<extension_removed_by_analyst>.txt", "note_full_text": "We are the RansomHub.
\n\nYour company Servers are locked and Data has been taken to our servers. This is serious. 
\n\nGood news:\n- your server system and data will be restored by our Decryption Tool, we supply 
trial decryption to prove that your files can be decrypted;\n- for now, your data is secured and
safely stored on our server;\n- nobody in the world is aware about the data leak from your company 
except you and RansomHub team;\n- we provide free trial decryption for files smaller than 1MB. If 
anyone claims they can decrypt our files, you can ask them to try to decrypt a file larger than 
1MB.\n\nFAQs:\nWho we are?\n- Normal Browser Links: https://ransomxifxwc5eteopdobynonjctkxvap77yqifu2emfbecbqdw6qd.onion.ly/\n- 
Tor Browser 
Links: 
http://ransomxifxwc5eteopdobynonjctkxvap77yqifu2emfbecbqdw6qd.onion/\n\nWant to go to authorities 
for protection?\n- Seeking their help will only make the situation worse,They will try to prevent 
you from negotiating with us, because the negotiations will make them look incompetent,After the 
incident report is handed over to the government department, you will be fined 
<This will be a huge amount,Read more about the GDRP legislation:https://
en.wikipedia.org/wiki/General_Data_Protection_Regulation> The government uses your fine to reward 
them.And you will not get anything, and except you and your company, the rest of the people will 
forget what happened!!!!!\n\nThink you can handle it without us by decrypting your servers and 
data using some IT Solution from third-party \"specialists\"?\n- they will only make significant 
damage to all of your data; every encrypted file will be corrupted forever. Only our Decryption 
Tool will make decryption guaranteed;\nDon't go to recovery companies, they are essentially just 
middlemen who will make money off you and cheat you. \n- We are well aware of cases where recovery 
companies tell you that the ransom price is 5 million dollars, but in fact they secretly negotiate 
with us for 1 million dollars, so they earn 4 million dollars from you. If you approached us 
directly without intermediaries you would pay 5 times less, that is 1 million dollars.\n\nThink 
your partner IT Recovery Company will do files restoration?\n- no they will not do restoration, 
only take 3-4 weeks for nothing; besides all of your data is on our server and we can publish it 
at any time; \n as well as send the info about the data breach from your company servers to your 
key partners and clients, competitors, media and youtubers, etc. \n Those actions from our side 
towards your company will have irreversible negative consequences for your business reputation.
\n\nYou don't care in any case, because you just don't want to pay? \n- We will make you business 
stop forever by using all of our experience to make your partners, clients, employees and whoever 
cooperates with your company change their minds by having no choice but to stay away from your 
company. \nAs a result, in midterm you will have to close your business. \n\nSo lets get straight 
to the point.\n\nWhat do we offer in exchange on your payment:\n- decryption and restoration of all 
your systems and data within 24 hours with guarantee;\n- never inform anyone about the data breach 
out from your company;\n- after data decryption and system restoration, we will delete all of your 
data from our servers forever;\n- provide valuable advising on your company IT protection so no 
one can hack you again.\n\nNow, in order to start negotiations, you need to do the following:\n- 
install and run 'Tor Browser' from https://www.torproject.org/download/\n- use 'Tor Browser' 
open <TA_URL_removed_by_analyst> \n- enter your ID or you will be banned and will never be able to 
decrypt your files.\n\nThere will be live chat for your company after successful negotiations for 
both sides. But there will be plenty of those bad cases of failed negotiations, so don't think about 
how to avoid it.\nJust focus on negotiations, payment and describe to make all of your problems 
solved by our specialists within 1 day after payment received: servers and data restored, 
everything will work good as new.\n\n************************************************\n",
"note_short_text": "Your data is stolen and encrypted, see README_<extension_removed_by_analyst>.txt.", "settings": 
  {"local_disks"

Data Leak Site

The RansomHub ransom note contains a data leak site (DLS) that displayed the following page, self-identifying the group as RansomHub:

Figure 5. TOR DLS

Similarities with Other Ransomware

During our analysis, we observed some similarities between RansomHub, ALPHV/BlackCat, and Knight ransomware executables.

The following table highlights some of the similarities:

Malware Family	Common Arguments	Password	JSON Configuration
RansomHub	pass safeboot safeboot-instance path help verbose fast path sleep	SHA256 strings value	extension note_file_name note_full_text note_short_text kill_processes kill_services credentials
ALPHV/BlackCat	–access-token (similar to -pass in RansomHub and Knight) safeboot safeboot-instance paths help verbose	SHA256 strings value	extension note_file_name note_full_text note_short_text kill_processes kill_services credentials
Knight	pass path verbose fast path sleep	SHA256 strings value	extension note_file_name note_full_text note_short_text kill_processes kill_services credentials

Detection Mechanisms

Custom Detections and Blocking with Arete’s Arsinal

SentinelOne S1QL 1.0 query syntax (STAR rule):

RansomHub Ransomware

EndpointOS = "windows" AND EventType = "Process Creation" AND TgtProcCmdLine RegExp 
"\.exe\s{1,3}[A-Za-z0-9-]{0,20}\s{0,3}-pass\s[A-Za-z0-9]{64}"

Volume Shadow Copy Deletion

EndpointOS = "windows" AND EventType = "Process Creation" AND TgtProcCmdLine Contains 
Anycase "powershell.exe" AND TgtProcCmdLine Contains Anycase "-Command" AND TgtProcCmdLine 
Contains Anycase "Get-CimInstance" AND TgtProcCmdLine Contains Anycase "Win32_ShadowCopy"

Windows Event Log Cleared 

EndpointOS = "windows" AND ObjectType = "process" AND TgtProcCmdLine Contains Anycase 
"wevtutil" AND TgtProcCmdLine Contains Anycase " cl " AND TgtProcCmdLine In Contains 
Anycase ("Application", "Security", "System")

SentinelOne S1QL 1.0 query syntax (STAR rule):

RansomHub Ransomware

EndpointOS = "windows" AND EventType = "Process Creation" AND TgtProcCmdLine RegExp 
"\.exe\s{1,3}[A-Za-z0-9-]{0,20}\s{0,3}-pass\s[A-Za-z0-9]{64}"

Volume Shadow Copy Deletion

EndpointOS = "windows" AND EventType = "Process Creation" AND TgtProcCmdLine Contains 
Anycase "powershell.exe" AND TgtProcCmdLine Contains Anycase "-Command" AND TgtProcCmdLine 
Contains Anycase "Get-CimInstance" AND TgtProcCmdLine Contains Anycase "Win32_ShadowCopy"

Windows Event Log Cleared 

EndpointOS = "windows" AND ObjectType = "process" AND TgtProcCmdLine Contains Anycase 
"wevtutil" AND TgtProcCmdLine Contains Anycase " cl " AND TgtProcCmdLine In Contains 
Anycase ("Application", "Security", "System")

SentinelOne S1QL 1.0 query syntax (STAR rule):

RansomHub Ransomware

EndpointOS = "windows" AND EventType = "Process Creation" AND TgtProcCmdLine RegExp 
"\.exe\s{1,3}[A-Za-z0-9-]{0,20}\s{0,3}-pass\s[A-Za-z0-9]{64}"

Volume Shadow Copy Deletion

EndpointOS = "windows" AND EventType = "Process Creation" AND TgtProcCmdLine Contains 
Anycase "powershell.exe" AND TgtProcCmdLine Contains Anycase "-Command" AND TgtProcCmdLine 
Contains Anycase "Get-CimInstance" AND TgtProcCmdLine Contains Anycase "Win32_ShadowCopy"

Windows Event Log Cleared 

EndpointOS = "windows" AND ObjectType = "process" AND TgtProcCmdLine Contains Anycase 
"wevtutil" AND TgtProcCmdLine Contains Anycase " cl " AND TgtProcCmdLine In Contains 
Anycase ("Application", "Security", "System")

Note: These threat hunting queries may need to be tuned for your specific network environment.

Yara

rule RansomHub_ransomware_executable
{

meta:

author = “areteir.com”
description = “Detects the RansomHub ransomware executable”
target = “Windows systems”
file_type = “exe”
copyright = “Copyright © 2024 by Arete Advisors, LLC.”
distribution = “No re-distribution without Arete Advisors, LLC consent.”

strings:

$s1 = “json:\”local_disks\””
$s2 = “json:\”running_one\””
$s3 = “json:\”self_delete\””
$s4 = “json:\”white_files\””
$s5 = “json:\”white_hosts\””
$s6 = “json:\”credentials\””
$s7 = “json:\”kill_services\””
$s8 = “json:\”set_wallpaper\””
$s9 = “json:\”white_folders\””
$s10 = “json:\”note_file_name\””
$s11 = “json:\”note_full_text\””
$s12 = “json:\”kill_processes\””
$s13 = “json:\”network_shares\””
$s14 = “json:\”note_short_text\””
$s15 = “json:\”master_public_key\””

condition:

((uint16(0) == 0x5A4D) and (uint32(uint32(0x3C)) == 0x00004550)) and
(9 of ($s*))

}

Recommended Mitigations

   - Utilize an endpoint detection and response (EDR) solution with the capability to halt detected processes
    and isolate systems on the network based on identified conditions.
   - Block any known attacker C2s in the firewall.
   - Implement multi-factor authentication on RDP and VPN to restrict access to critical network resources.
   - Eliminate unnecessary RDP ports exposed to the internet.
   - Block a high number of SMB connection attempts from one system to others in the network over a short period of time.
   - Perform periodic dark web monitoring to verify if data is available for sale on the black market.
   - Perform penetration tests.
   - Periodically patch systems and update tools.
   - Monitor connections to the network from suspicious locations.
   - Monitor downloads and uploads of files to file-sharing services outside standard work hours.
   - Monitor file uploads from domain controllers to the internet.
   - Monitor network scans from uncommon servers (e.g., RDP server)

   - Utilize an endpoint detection and response (EDR) solution with the capability to halt detected processes
    and isolate systems on the network based on identified conditions.
   - Block any known attacker C2s in the firewall.
   - Implement multi-factor authentication on RDP and VPN to restrict access to critical network resources.
   - Eliminate unnecessary RDP ports exposed to the internet.
   - Block a high number of SMB connection attempts from one system to others in the network over a short period of time.
   - Perform periodic dark web monitoring to verify if data is available for sale on the black market.
   - Perform penetration tests.
   - Periodically patch systems and update tools.
   - Monitor connections to the network from suspicious locations.
   - Monitor downloads and uploads of files to file-sharing services outside standard work hours.
   - Monitor file uploads from domain controllers to the internet.
   - Monitor network scans from uncommon servers (e.g., RDP server)

   - Utilize an endpoint detection and response (EDR) solution with the capability to halt detected processes
    and isolate systems on the network based on identified conditions.
   - Block any known attacker C2s in the firewall.
   - Implement multi-factor authentication on RDP and VPN to restrict access to critical network resources.
   - Eliminate unnecessary RDP ports exposed to the internet.
   - Block a high number of SMB connection attempts from one system to others in the network over a short period of time.
   - Perform periodic dark web monitoring to verify if data is available for sale on the black market.
   - Perform penetration tests.
   - Periodically patch systems and update tools.
   - Monitor connections to the network from suspicious locations.
   - Monitor downloads and uploads of files to file-sharing services outside standard work hours.
   - Monitor file uploads from domain controllers to the internet.
   - Monitor network scans from uncommon servers (e.g., RDP server)

Organizations can find the full list of US government-recommended ransomware prevention and mitigation guidance here: https://www.cisa.gov/stopransomware/ransomware-guide

Arete provides data-driven cybersecurity solutions to transform your response to emerging cyber threats.

Click here to learn more.

References

At Arete, we envision a world without cyber extortion, where people, businesses, and governments can thrive. We are taking all that we know from over 9,000 engagements to inform our solutions and strengthen powerful tools to better prevent, detect, and respond to the cyber extortion threats of tomorrow. Our elite team of experts provides unparalleled capabilities to address the entire cyber threat lifecycle, from incident response and restoration to advisory and managed security services. To learn more about our solutions, visit www.areteir.com.

Back to Blog Posts

Article

Apr 17, 2026

Phishing-as-a-Service Evolves with Venom

“Whaling” has taken on a new meaning with a highly targeted phishing campaign active from November 2025 through March 2026, aimed exclusively at senior executives from more than 20 industries. The campaign, dubbed VENOM, is a phishing-as-a-service (PhaaS) platform that combines advanced evasion capabilities with immediate persistence of targeted executives. The initial phish impersonates an internal SharePoint document notification and uses embedded QR codes to convince victims to shift to unmanaged mobile devices to bypass corporate security controls. VENOM aims to establish persistence immediately by either registering a new MFA device or retaining long-lived refresh tokens, allowing threat actors to maintain access even after password resets or other base-level remediation efforts.

What’s Notable and Unique

This campaign is unique in its targeted nature of the PhaaS platform rather than broad, sweeping attempts. The threat actors behind VENOM create convincing phishing emails that impersonate SharePoint activity using the victim’s own domain, company name, and even fabricated email threads. These convincing social engineering tactics, combined with the specific targeting of executives, make this an effective capability for cybercriminals.

VENOM operates as a closed-access system, with full adversarial support, but has no public visibility on the dark web or from security researchers. The service likely operates on an invite-only basis, unlike most PhaaS platforms, which typically seek to have as many paying customers as possible. This, among other items such as the sophisticated evasion techniques, indicates a higher degree of sophistication than most other PhaaS offerings.

Either through MFA enrollment or Microsoft Device Code abuse, the threat actor forces the victim to aid them in establishing persistence early in the attack lifecycle. These tactics result in either valid tokens or an additional MFA login method controlled by the threat actor, meaning typical password resets alone are not effective against this technique. Administrators would be required to explicitly revoke sessions and token grants to mitigate the threat actors’ persistence.

Analyst Comments

Oftentimes, MFA is viewed as a one-stop shop to cybersecurity, but tactics such as this show how threat actors can bypass MFA, or worse, use it to establish persistence. Ultimately, this campaign highlights how modern attacks increasingly abuse legitimate authentication workflows rather than attempting to defeat them outright. Defenses that rely solely on MFA without other security posturing, such as continuous session monitoring, token revocation, and identity logging, can leave organizations vulnerable. As attackers shift toward token theft and device trust abuse, incident response and identity security strategies must evolve accordingly.

Sources

Meet VENOM: The PhaaS Platform That Neutralizes MFA

Article

Apr 14, 2026

Threat Actors Continue to Leverage BYOVD Technique

Multiple ransomware operations have recently been observed leveraging the Bring Your Own Vulnerable Driver (BYOVD) technique to disable endpoint security controls prior to ransomware deployment. Notably, the Qilin ransomware group commonly leverages a malicious msimg32.dll file loaded via DLL side-loading, along with vulnerable drivers including rwdrv.sys and hlpdrv.sys, to gain kernel-level access and disable security processes. Similarly, Warlock ransomware has been observed exploiting the vulnerable NSecKrnl.sys driver to bypass security controls. The use of BYOVD has also been observed across ransomware campaigns associated with Akira, INC, Medusa, and other threat actors.

What’s Notable and Unique

The Qilin ransomware group employs a sophisticated multi-stage infection chain, leveraging DLL side-loading (msimg32.dll) to execute malicious payloads directly in memory and evade traditional file-based detection. In DLL side-loading, a threat actor tricks a program into loading a malicious dynamic link library. The malware escalates privileges and uses signed but vulnerable drivers (rwdrv.sys and hlpdrv.sys) to bypass security controls, access system memory, and systematically disable endpoint defenses by terminating security processes and disabling monitoring callbacks at the kernel level.

Akira ransomware operators have also exploited the rwdrv.sys and hlpdrv.sys drivers. Additionally, Arete has observed threat actors leveraging multiple other drivers, including the vulnerable TrueSight.sys, to bypass security controls.

Meanwhile, Warlock ransomware operators disguised malicious activity by renaming rclone.exe to TrendSecurity.exe to appear legitimate. The file functioned as a loader, exploiting the vulnerable NSecKrnl.sys driver to disable security processes, while Group Policy Objects (GPOs) were leveraged to systematically disable security controls across the environment.

Analyst Comments

The BYOVD technique, employed by multiple known ransomware operators, reflects a broader shift toward pre-encryption defense evasion, including suppression of Windows telemetry, removal of monitoring callbacks, and abuse of legitimately signed but vulnerable drivers. This technique enables threat actors to evade detection, maintain persistence for extended periods, and maximize the operational impact of ransomware deployment across compromised environments. Organizations should implement strict driver control policies, such as Microsoft’s Vulnerable Driver Blocklist and application control mechanisms. Additionally, enforcing least privilege access, enabling multi-factor authentication (MFA), maintaining up-to-date patching, and continuously monitoring for anomalous driver and kernel-level activity can further reduce the risk of such attacks.

Sources

Qilin EDR killer infection chain
Web Shells, Tunnels, and Ransomware: Dissecting a Warlock Attack

Article

Apr 6, 2026

Ransomware Trends & Data Insights: March 2026

The threat landscape in March had a much more even distribution of threat groups than has been observed since the first half of 2025. Although Akira, Qilin, Play, and INC remained among the most active groups, Arete observed 21 unique ransomware and extortion groups in March, compared to only 15 in February. Akira and Qilin’s activity also declined from the previous month; in February, the two groups were responsible for almost half of all ransomware incidents, but in March they only comprised a little more than a quarter of all activity. Arete also observed activity from several emerging groups in the past month, including BravoX, NightSpire, Payouts King, and Securotrop.

Figure 1. Activity from the top 5 threat groups in March 2026

Analysts at Arete identified several trends behind the threat actors perpetrating cybercrime activities:

In March, threat actors actively exploited FortiGate Next-Generation Firewall appliances as initial access vectors to compromise enterprise networks. The activity involves the exploitation of recently disclosed security vulnerabilities, including CVE-2025-59718, CVE-2025-59719, and CVE-2026-24858, or weak credentials, allowing attackers to gain administrative access, extract configuration files, and obtain service account credentials. Arete also observed Fortinet device exploitation involving various threat groups, with the Qilin ransomware group notably leveraging Fortinet device exploits.
Phishing campaigns leveraging OAuth redirection and a resurgence of Microsoft Teams–based social engineering were also observed in March. In one campaign, attackers sent emails disguised as Microsoft Teams recordings or Microsoft 365 alerts, redirecting victims through legitimate OAuth endpoints to attacker-controlled pages hosting malicious ZIP payloads. A separate campaign has been ongoing since last year, in which attackers flood users’ inboxes with spam and impersonate IT support personnel to trick victims into initiating remote support sessions via tools like Quick Assist.
Arete recently released its 2025 Annual Crimeware Report. Leveraging data and intelligence collected during ransomware and extortion incident response engagements, this report highlights notable trends and shifts in the threat landscape throughout 2025, including Akira’s unusually high activity levels in the second half of 2025, evolving social engineering techniques, and trends in ransom demands and impacted industries.

Sources

Arete Internal

Report

Mar 27, 2026

Arete's 2025 Annual Crimeware Report

Harness Arete’s unique data and expertise on extortion and ransomware to inform your response to the evolving threat landscape.