Kooijman Vianen (kooijmanvianen.nl) Listed by fog Ransomware Group: Ransomware Claim — What’s Alleged & What To Do

Kooijman Vianen, the Dutch organisation operating at kooijmanvianen.nl, was listed on 23 January 2025 by the ransomware group known as fog. Public reporting states that the group claims to have exfiltrated 25.7 GB of internal files during a ransomware attack. The number of people affected remains unknown, and further technical details of the incident have not been disclosed.

The listing itself constitutes a claim by the group rather than independent confirmation. Even so, any confirmed or claimed compromise of internal business files raises practical concerns for employees, partners and clients whose information may have been among the data taken.

What happened

According to the available record, Kooijman Vianen appeared on fog’s leak site on 23 January 2025. The group asserts that it carried out a ransomware attack in which 25.7 GB of internal files were exfiltrated. No public information has been released about the precise date of the intrusion, the initial access method, whether systems were encrypted, or whether a ransom demand was made or paid. The number of individuals whose data may have been involved is listed as unknown. Beyond the volume figure and the description “internal files,” no further inventory of the material has been published by either the organisation or the group.

The group behind it: fog

Fog is a ransomware operation that has been active in public reporting since mid-2024. Like many contemporary ransomware groups, it typically employs a double-extortion model: data is copied from the victim’s network before encryption is applied, and the stolen material is then used as leverage. Victims who do not meet the group’s demands risk having portions of the data published on fog’s dedicated leak site. The group has previously listed organisations across manufacturing, logistics, professional services and other sectors, often advertising the volume of data claimed to have been taken. Its postings are self-reported claims; independent verification of the contents or completeness of any given dump is rarely available at the time of listing. In this instance, fog’s sole public statement regarding Kooijman Vianen is the leak-site entry itself, which cites the 25.7 GB figure and the characterisation of the material as internal files.

About Kooijman Vianen (kooijmanvianen.nl)

Kooijman Vianen is a Dutch company whose public-facing website is kooijmanvianen.nl. Organisations of this type commonly operate in industrial or commercial supply chains—frequently involving specialised equipment, construction-related products or logistics services—and therefore maintain internal records that include employee details, customer and supplier contracts, project documentation, financial information and operational correspondence. Because such firms sit at the intersection of multiple business relationships, a compromise of their internal systems can affect not only their own staff but also the partners and clients whose data they hold in the ordinary course of business. The consequential nature of a breach here stems less from any single high-profile consumer database and more from the density of commercial and personal information that mid-sized industrial or service companies typically process.

What was likely exposed

The only data type explicitly named in the public record is “internal files” totalling 25.7 GB. No further breakdown—such as whether the material included personnel records, invoices, emails, technical drawings or customer databases—has been confirmed. Organisations comparable to Kooijman Vianen ordinarily store a mixture of human-resources files, commercial contracts, correspondence and operational documents. It is therefore reasonable to expect that some combination of those categories could have been among the exfiltrated volume, yet the exact contents remain unconfirmed. Readers should treat any more specific claims circulating outside the official record as unverified.

The real-world impact

For individuals whose personal or professional details may have been present, the primary risks are opportunistic misuse of contact information, identity-related fraud if identifiers were included, and targeted phishing that leverages knowledge of the company’s internal structure or projects. For the organisation itself, the consequences can include operational disruption, contractual notification obligations under European data-protection rules, reputational damage among clients and suppliers, and the cost of forensic investigation and remediation. Because the number of affected people is unknown and the precise file inventory has not been published, the full scope of these risks cannot yet be quantified. The incident nonetheless illustrates how even a mid-sized firm’s internal repository can become a vector for broader exposure once it leaves the organisation’s control.

If your data was in this claimed breach

If you have a past or present relationship with Kooijman Vianen—as an employee, contractor, customer or supplier—treat the possibility of exposure seriously until more detail emerges. Change passwords associated with any accounts that used the same credentials as work systems, enable multi-factor authentication wherever available, and remain alert for unexpected messages that reference company projects or colleagues. Monitor financial statements and credit reports for unusual activity. You can also run a free exposure scan of your email address to check whether that address has already appeared in known breach data sets; such a scan provides an additional, independent signal while official notifications, if any, are still pending.

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