MultiMasters Listed by cactus Ransomware Group: Ransomware Claim — What’s Alleged & What To Do

People whose details sit inside MultiMasters’ systems face a practical problem: a ransomware group has publicly claimed the company as a victim and says internal files were taken. When the number of people affected is unknown and the precise contents of those files remain unconfirmed, the immediate concern is straightforward—whether personal, contractual or operational information has left the organisation’s control and could be misused.

On 9 October 2023 MultiMasters appeared on a listing associated with the cactus ransomware group. Public detail is limited; what is known is the claim of exfiltration and the organisation’s place in Belgium’s business-support sector. That combination is enough to warrant clear, calm attention from anyone who has dealt with the company.

What happened

According to the available record, MultiMasters was listed by the cactus ransomware group on 9 October 2023. The report states that internal files were exfiltrated in a ransomware attack. No confirmed figure for the number of people affected has been published, and the precise method of intrusion, the duration of any access, and the full scope of systems involved have not been disclosed in the material at hand.

The listing itself constitutes a claim by the group. Independent confirmation of the volume or sensitivity of the data, or of any subsequent public release, is not provided in the facts. What can be stated is that the organisation was named and that exfiltration of internal files was asserted as part of the incident.

Inside cactus

Cactus is a ransomware operation that has been observed using double-extortion tactics: encrypting systems while also copying data and threatening to publish or sell it if demands are not met. The group typically maintains a leak site on which it names victims and, in some cases, releases samples or larger archives. Its activity has been documented across multiple sectors and countries; the pattern is consistent with other contemporary ransomware crews that prioritise both operational disruption and data leverage.

In this instance the group claims MultiMasters as a victim and asserts that internal files were taken. No further statements attributed specifically to cactus about this organisation—such as ransom amounts, deadlines, or proof-of-compromise details—appear in the supplied record. The listing should therefore be treated as an unverified claim pending additional corroboration.

About MultiMasters

MultiMasters, also referred to as the Multi Masters Group, is a Belgian business-support company with roots in the cleaning sector. It evolved from Cleaning Masters, a family business founded in 1988 that grew into one of Belgium’s larger providers of facility and support services. In 2004 it became part of the Samsic Group, a European services organisation, and it also participates in AAFM, a European cooperation platform for business-support services. The company operates across multiple locations in Belgium and offers a range of outsourced services to commercial clients.

Organisations of this type routinely hold employee records, client contracts, operational schedules, invoicing data and, in many cases, access credentials or site-specific information needed to deliver services on customer premises. A breach involving such a firm is consequential because the data often spans both the company’s own workforce and the businesses it serves, creating secondary exposure paths that extend beyond a single corporate boundary.

What was likely exposed

The facts name the exposed material as internal files exfiltrated in a ransomware attack. No itemised inventory of those files has been published in the available record, and the number of individuals affected remains unknown. Exact contents are therefore unconfirmed.

Companies in the business-support and facilities sector typically maintain:

• Employee personal and payroll information
• Client contracts, service schedules and site access details
• Invoicing, financial and supplier records
• Internal operational documents and correspondence

Any of the above could fall under the broad description “internal files,” yet none can be asserted as definitively present in the stolen set without further disclosure. Readers should treat the exposure as real in principle and undefined in detail.

The real-world impact

For individuals, the practical risks include possible misuse of personal data for phishing, identity fraud or targeted social engineering, especially if employment or contact details were among the files. Clients of MultiMasters may face secondary concerns if contractual or site-related information was included, potentially exposing their own operations or staff. Because the scale is undisclosed, it is not possible to quantify how many people sit in either category.

For the organisation the consequences are operational and reputational: disruption from any encryption event, the cost of investigation and remediation, notification obligations where applicable, and the longer-term erosion of trust among employees and commercial partners. None of these outcomes requires assuming negligence; they follow from the simple fact that internal material is claimed to have left the organisation’s control.

Were you affected?

If you are a current or former employee, contractor or client of MultiMasters, treat the possibility of exposure as credible until clearer information emerges. Monitor financial and email accounts for unusual activity, be cautious of unexpected messages that reference the company or its services, and consider placing fraud alerts with relevant credit or identity services if you believe sensitive personal data may have been involved. You can also run a free exposure scan of your email address to check whether it has already appeared in known breach datasets. Public detail on this incident remains limited; further official statements from the company or regulators, if issued, will be the most reliable source of updates.

AICompiled with AI assistance from public sources and published under our editorial standards.