FortiGuard Labs Threat Research

New Supply Chain Ransomware Attack Targets Kaseya Platform

By Jonathan Nguyen-Duy | July 04, 2021

FortiGuard Labs Breaking Update

In July 2021, a new global supply chain ransomware attack targeted users of the Kaseya VSA platform—software that provides remote management of IT operations spanning service desk ticketing to performance monitoring and reporting. As a central management console, the Kaseya VSA platform is used by numerous managed service providers to remotely monitor and deploy software, updates, etc. to multiple machines simultaneously in a multi-user environment. 

Unofficial reports have identified the REvil ransomware threat actors as being behind this supply chain attack. REvil has been attributed to the DarkSide actors who most recently attacked Colonial Pipeline and JBS foods back in May. Those same unofficial reports claim that a malicious update was deployed to the Kaseya VSA interface by the threat actors as an update or hotfix for the Kaseya VSA agent. This fake update is a ransomware file, and it has now been downloaded to thousands of systems, including the machines of MSP providers and their customers who use Kaseya VSA. There are reports of ransom demands of $50,000 for smaller organizations and up to $5 million for larger enterprises.

Kaseya is urging all customers to take all on-premises VSA servers offline immediately. Only on-premises systems have been impacted by this attack.Cloud-based SaaS services remain unaffected. The Kaseya advisory reads in part:


Reports of the attack first surfaced when Huntress Labs, a managed detection and response (MDR) provider, first discovered the attack and posted their findings on Reddit. Timing the attack for the Independence Day holiday in the United States, this supply chain ransomware attack has impacted hundreds of organizations worldwide, both large and small, across all industries and managed service providers.

What was the Kaseya Ransomware Attack?

This sophisticated supply-chain ransomware attack initially leveraged a vulnerability in the Kaseya VSA software to gain access to victim organizations, and then used REvil’s RaaS to infect those organizations with ransomware. For that reason, FortiGuard Labs provided a separate Outbreak Alert analysis for both the initial exploitation of the Kaseya vulnerability and for the subsequent REvil ransomware attack. Each Outbreak Alert includes information about the attack itself, Fortinet product versions that provide protection, which products could break the attack sequence, threat hunting techniques, and other information. 

To learn more, go here for the Kaseya Outbreak Alert and here for the REvil Outbreak Alert.

Threat Indicators for the Kaseya Supply Chain Attack

Threat indications that you should be aware of include:

  • Initial notifications indicate that the "KElevated######" (SQL User) account performed this action.
  • VSA admin user accounts are disabled only moments before ransomware is deployed
  • Ransomware encryptor is dropped to c:\kworking\agent.exe
  • The VSA procedure is named "Kaseya VSA Agent Hot-fix”
  • At least two tasks run the following: 
    • C:\WINDOWS\system32\cmd.exe /c ping -n 4979 > nul
    • C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe Set-MpPreference -DisableRealtimeMonitoring $true -DisableIntrusionPreventionSystem $true -DisableIOAVProtection $true -DisableScriptScanning $true -EnableControlledFolderAccess Disabled -EnableNetworkProtection AuditMode -Force -MAPSReporting Disabled -SubmitSamplesConsent NeverSend
    • copy /Y C:\Windows\System32\certutil.exe C:\Windows\cert.exe
    • echo %RANDOM% >> C:\Windows\cert.exe
    • C:\Windows\cert.exe -decode c:\kworking\agent.crt c:\kworking\agent.exe
    • del /q /f c:\kworking\agent.crt C:\Windows\cert.exe & c:\kworking\agent.exe

In addition, the encryptor (agent.exe) is signed with a valid digital signature that includes the following information:

  • Email:
  • CN = Sectigo RSA Code Signing, CAO = Sectigo Limited, L = Salford, S = Greater Manchester, C = GB
  • Serial #: 119acead668bad57a48b4f42f294f8f0
  • Issuer:

When agent.exe runs, the following files are dropped into the hardcoded path C:\Windows:

  • MsMpEng.exe - the legit Windows Defender executable
  • mpsvc.dll - the encryptor payload that is sideloaded by the legit Defender .EXE


Fortinet strongly recommends organizations using the Kaseya VSA platform to implement the current guidance in Kaseya's official recommendation"IMMEDIATELY shutdown your VSA server until you receive further notice from [Kaseya].”

Fortinet Protections

While the Kaseya VSA supply chain attack is how the threat actors got into the different networks, the ransomware used in those attacks is blocked by FortiGuard Labs through its AV coverage against known publicly available samples as: 

  • W32/Sodinokibi.EAD4!tr.ransom
  • W32/Sodinokibi.8859!tr.ransom
  • W32/Sodinokibi.5421!tr.ransom

FortiGuard Labs has IPS coverage in place as: Kaseya.VSA.Remote.Code.Execution

All known network IOCs are blocked by the WebFiltering client.

The FortiGuard AntiVirus service is supported by FortiGateFortiMail, FortiClient, and FortiEDR. The Fortinet AntiVirus engine is a part of each of those solutions as well. As a result, customers who have these products with up-to-date protections are protected.

For FortiEDR protections, all published IOCs have been added to our Cloud intelligence service and will be blocked if executed on customer systems.

The FortiGuard Responder team has published a Knowledge Base analysis on Kaseya and “How FortiEDR detects Kaseya supply chain ransomware attack.”

For FortiSandbox, all publicly known ransomware samples are detected by our behavior-based protection.


The following advisory was posted by Kaseya: Information Regarding Potential Attack on Kaseya VSA

The following FortiGuard Threat Signal report contains the latest information about this ransomware attack as well as updated information about FortiGuard Labs protections: Global Ransomware and Supply Chain Attack on Kaseya VSA Affecting Multiple Organizations


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