Ransomware actor exploited RMM to access multiple organizations; Sophos EDR blocked encryption on customer’s network
Sophos MDR recently responded to a targeted attack involving a Managed Service Provider (MSP). In this incident, a threat actor gained access to the MSP’s remote monitoring and management (RMM) tool, SimpleHelp, and then used it to deploy DragonForce ransomware across multiple endpoints. The attackers also exfiltrated sensitive data, leveraging a double extortion tactic to pressure victims into paying the ransom.
Sophos MDR has medium confidence the threat actor exploited a chain of vulnerabilities that were released in January 2025:
CVE-2024-57727: Multiple path traversal vulnerabilities
CVE-2024-57728: Arbitrary file upload vulnerability
CVE-2024-57726: Privilege escalation vulnerability
DragonForce
DragonForce ransomware is an advanced and competitive ransomware-as-a-service (RaaS) brand that first emerged in mid-2023. As discussed in recent research from Sophos Counter Threat Unit (CTU), DragonForce began efforts in March to rebrand itself as a “cartel” and shift to a distributed affiliate branding model.
Coinciding with this effort to appeal to a wider range of affiliates, DragonForce recently garnered attention in the threat landscape for claiming to “take over” the infrastructure of RansomHub. Reports also suggest that well-known ransomware affiliates, including Scattered Spider (UNC3944) who was formerly a RansomHub affiliate, have been using DragonForce in attacks targeting multiple large retail chains in the UK and the US.
The incident
Sophos MDR was alerted to the incident by detection of a suspicious installation of a SimpleHelp installer file. The installer was pushed via a legitimate SimpleHelp RMM instance, hosted and operated by the MSP for their clients. The attacker also used their access through the MSP’s RMM instance to gather information on multiple customer estates managed by the MSP, including collecting device names and configuration, users, and network connections.
One client of the MSP was enrolled with Sophos MDR and had Sophos XDR endpoint protection deployed. Through a combination of behavioral and malware detection and blocking by Sophos endpoint protection and MDR actions to shut down attacker access to the network, thwarting the ransomware and double extortion attempt on that customer’s network. However, the MSP and clients that were not using Sophos MDR were impacted by both the ransomware and data exfiltration. The MSP engaged Sophos Rapid Response to provide digital forensics and incident response on their environment.
The Gootloader malware family uses a distinctive form of social engineering to infect computers: Its creators lure people to visit compromised, legitimate WordPress websites using hijacked Google search results, present the visitors to these sites with a simulated online message board, and link to the malware from a simulated “conversation” where a fake visitor asks a fake site admin the exact question that the victim was searching for an answer to.
Sophos Managed Detection and Response initiated a threat hunt across all customers after the detection of abuse of a vulnerable legitimate VMware executable (vmnat.exe) to perform dynamic link library (DLL) side-loading on one customer’s network. In a search for similar incidents in telemetry, MDR ultimately uncovered a complex, persistent cyberespionage campaign targeting a high-profile government organization in Southeast Asia. As described in the first part of this report, we identified at least three distinct clusters of intrusion activity present in the organization’s network from at least March 2023 through December 2023.
The three security threat activity clusters—which we designated as Alpha (STAC1248), Bravo (STAC1870), and Charlie (STAC1305) – are assessed with high confidence to operate on behalf of Chinese state interests. In this continuation of our report, we will provide deeper technical analysis of the three activity clusters, including the tactics, techniques, and procedures (TTPs) used in the campaign, aligned to activity clusters where possible. We also provide additional technical details on prior compromises within the same organization that appear to be connected to the campaign.
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