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Cyber Threat
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Ransomware victim Construction

Söllner

Listed by Sarcoma on · organisation based in Germany

soellner.de

Disclosed
Nov 20, 2025
Leak-site listing date
Threat group
Sarcoma
144 victims listed
Country
Germany
#2 most targeted
Sector
Construction

ThreatAI analysis

Compiled from this incident record and the threat intelligence profile for Sarcoma. Figures and technique mappings are quoted from the source data, not inferred.

About the Sarcoma group

Sarcoma is a ransomware group that debuted in October 2024, immediately ranking among the top three most active groups globally and surpassing 116 documented victims by mid-2025, targeting mid-market companies across manufacturing, retail, healthcare, legal, and business services with roughly 50% of victims in the United States. Sarcoma has listed 141 victims since July 2024.

How Sarcoma is documented to operate

Valid Accounts T1078 Stealth Persistence

Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Compromised credentials may be used to bypass access controls placed on various resources on systems within the network and may even be used for persistent access to remote systems and externally available services, such as VPNs, Outlook Web Access, network devices, and remote desktop. Compromised credentials may also grant an adversary increased privilege to specific systems or access to restricted areas of the network.

Mitigations: Application Developer Guidance, User Training, Password Policies, User Account Management, Privileged Account Management, Multi-factor Authentication

MITRE ATT&CK reference
Exploit Public-Facing Application T1190 Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network. The weakness in the system can be a software bug, a temporary glitch, or a misconfiguration. Exploited applications are often websites/web servers, but can also include databases (like SQL), standard services (like SMB or SSH), network device administration and management protocols (like SNMP and Smart Install), and any other system with Internet-accessible open sockets. On ESXi infrastructure, adversaries may exploit exposed OpenSLP services; they may alternatively exploit exposed VMware vCenter servers.

Mitigations: Vulnerability Scanning, Limit Access to Resource Over Network, Filter Network Traffic, Network Segmentation, Privileged Account Management, Application Isolation and Sandboxing

MITRE ATT&CK reference
Trusted Relationship T1199 Initial Access

Adversaries may breach or otherwise leverage organizations who have access to intended victims. Access through trusted third party relationship abuses an existing connection that may not be protected or receives less scrutiny than standard mechanisms of gaining access to a network. Organizations often grant elevated access to second or third-party external providers in order to allow them to manage internal systems as well as cloud-based environments. Some examples of these relationships include IT services contractors, managed security providers, infrastructure contractors (e.g. HVAC, elevators, physical security).

Mitigations: Network Segmentation, User Account Management, Multi-factor Authentication

MITRE ATT&CK reference
Phishing T1566 Initial Access

Adversaries may send phishing messages to gain access to victim systems. All forms of phishing are electronically delivered social engineering. Phishing can be targeted, known as spearphishing. In spearphishing, a specific individual, company, or industry will be targeted by the adversary. More generally, adversaries can conduct non-targeted phishing, such as in mass malware spam campaigns. Adversaries may send victims emails containing malicious attachments or links, typically to execute malicious code on victim systems. Phishing may also be conducted via third-party services, like social media platforms.

Mitigations: Network Intrusion Prevention, Restrict Web-Based Content, User Training, Antivirus/Antimalware, Software Configuration, Audit

MITRE ATT&CK reference
Scheduled Task/Job T1053 Execution Persistence

Adversaries may abuse task scheduling functionality to facilitate initial or recurring execution of malicious code. Utilities exist within all major operating systems to schedule programs or scripts to be executed at a specified date and time. A task can also be scheduled on a remote system, provided the proper authentication is met (ex: RPC and file and printer sharing in Windows environments). Scheduling a task on a remote system typically may require being a member of an admin or otherwise privileged group on the remote system. Adversaries may use task scheduling to execute programs at system startup or on a scheduled basis for persistence.

Mitigations: Operating System Configuration, User Account Management, Restrict File and Directory Permissions, Privileged Account Management, Audit

MITRE ATT&CK reference

MITRE ATT&CK techniques attributed to Sarcoma across its recorded activity, not a finding about how Söllner was reached.

Incident analysis

Söllner was listed by Sarcoma ransomware, a group with 144 victims recorded in this database. The listing appeared on the group's leak site on November 20, 2025.

Söllner is based in Germany and operates in the Construction sector. Germany ranks #2 worldwide for ransomware disclosures, with 1,041 victims in this database.

Sector context. Construction firms often hold sensitive project data, client financials, and intellectual property. The industry's typically lean IT security teams can make them more vulnerable.

Sarcoma typically follows a double extortion model: data is exfiltrated from the victim's systems before files are encrypted, so the victim faces two demands at once — pay to restore access, and pay to keep stolen data unpublished. The leak site, where this listing appeared, is the lever for the second demand.

Source. Public leak-site disclosures aggregated via the ransomware.live API. The disclosure date is when the listing was published, which can differ from the date of compromise. This site does not publish or link to stolen data. Last updated .

Frequently asked questions

Was Söllner attacked by ransomware?

Yes. Söllner was listed as a victim of the Sarcoma ransomware group on November 20, 2025. The organisation is based in Germany and operates in the Construction sector. The disclosure appeared on the group's dark web leak site.

Which ransomware group attacked Söllner?

Söllner was attacked by Sarcoma ransomware. Sarcoma is one of the most active ransomware groups, having claimed 144 victims globally. The group typically employs a double-extortion model: encrypting the victim's files and threatening to publish stolen data.

When did the Söllner ransomware attack occur?

The ransomware attack on Söllner was disclosed on November 20, 2025. This date reflects when the victim was published on the threat group's leak site, which may differ from the actual date of initial compromise.

What data was stolen in the Söllner ransomware attack?

The specific data stolen from Söllner has not been independently verified by this platform. Ransomware groups typically exfiltrate data before encrypting systems and use the threat of publication to pressure victims. As a Construction organisation, Söllner likely held sensitive business data, client information, and operational records.

How can organisations protect against Sarcoma attacks?

To defend against Sarcoma and similar threat actors, organisations should: maintain regular offline backups tested for restoration; implement network segmentation to limit lateral movement; deploy multi-factor authentication on all remote access; use endpoint detection and response (EDR) tools; conduct regular phishing and security awareness training; and monitor threat intelligence feeds for indicators of compromise (IOCs) associated with active groups.