Buying an apartment and losing your identity? What the Dom Development data breach teaches us
Introduction: From Dream Home to Digital Nightmare
Buying an apartment is one of the most significant moments in life. Emotions, plans for the future, a sense of security—all these intertwine in the decision to own a home. At that moment, hardly anyone thinks about servers, databases, or cybersecurity. Yet, as the incident at Dom Development—one of Poland's largest developers—has shown, these two worlds are inextricably linked. The hacking attack, the detection of which was announced by the company on December 4, 2025, is not just a corporate problem. It is a personal threat to thousands of clients, employees, and contractors who likely never expected that their digital identity was also at stake in the game for their apartment. This leak reveals a surprising and disturbing truth about how deeply our private lives are connected to the companies we trust. In this analysis, we will look at the most shocking aspects of this incident and suggest how to protect yourself from its consequences.
Dom Development S.A. is a leading Polish residential developer, operating in the construction market since 1996, with its headquarters located in Warsaw. The company is one of the largest in its industry in Poland, specializing in the construction and sale of apartments in both the popular and premium segments. Dom Development operates in key Polish cities, executing projects in Warsaw, as well as through its subsidiaries in the Tricity (via Euro Styl S.A.), Wrocław (e.g., Dom Development Wrocław Sp. z o.o.), and Kraków (e.g., Dom Development Kraków Sp. z o.o.). Since 2006, Dom Development S.A. has been a publicly listed company on the Warsaw Stock Exchange (GPW).
1. The Biggest Surprise: Data Leaked Not Just from You, But from Your Children
When we hear about data leaks, we instinctively think about our own security: my bank account, my PESEL number, my email address. The incident at Dom Development brutally breaks this pattern. Its most terrifying aspect is the fact that not only the data of people directly associated with the company is at risk, but also the data of their family members, including minors. This is a completely new, much more personal level of threat.
According to information provided by the company, the attack may have resulted in the theft of extremely sensitive data regarding the families of employees and associates. The scale of this information is shocking:
- Employees' Children: Full names, dates of birth, PESEL numbers, and residential addresses.
- Other family members and life partners: Name and surname, date of birth, PESEL number, and information on the degree of kinship.
What does this mean in practice? Child identity theft is particularly perfidious and dangerous. A child's PESEL number is "clean"—it has no credit history or obligations. For fraudsters, it is an ideal tool for taking out long-term loans or setting up shell companies. Worse still, such a practice can go undetected for years, and its consequences can be devastating. Imagine a situation where a young person entering adulthood finds out they cannot get a student loan, open their first credit card, or even pass an employment background check because their identity was ruined long ago. The scope of adult data that fell into the wrong hands was equally alarming.
2. "Identity Theft Kit": What Exactly Leaked?
The list of stolen information alone does not fully reflect the seriousness of the situation. Only the combination of all these elements creates what can be called a complete "digital identity theft kit." This is a powerful tool in the hands of criminals, allowing for much more than just obtaining a quick payday loan. Let's look at exactly what may have been stolen, as the scope goes far beyond standard information.
For Clients and Contractors:
In the case of people who bought an apartment, negotiated a contract, or collaborated with the developer, the data package allows for the creation of a full financial, property, and even personal profile.
- Personal Data: Name, surname, PESEL, ID card number and series, parents' names, marital status.
- Financial Data: Bank account number, debt amount, information on transactions, financing, and payments.
- Property Data: Land and Mortgage Register number (Numer księgi wieczystej), real estate addresses, and even details regarding co-ownership (statutory joint ownership or separation of property).
- Contact and Digital Data: Residential and registered address, email, phone number, IP address.
- Sensitive and Behavioral Data: Information on purchasing preferences, and most shockingly—the statement mentions that health-related data may have also appeared in the dataset.
For Employees and B2B Associates:
Personnel data is equally sensitive and provides insight not only into the entire career path but also into the most private spheres of life.
- Identification Data: Name, surname, PESEL, NIP (Tax ID), ID card number and series along with the image, student ID numbers.
- Employment Data: Full history of employment and education, information on participation in training, professional qualifications held, or use of benefits (including participation in PPK and ZFŚS).
- Financial Data: Salary amount, bank account number, information on bonuses, deductions, tax relief, and even bailiff seizures.
- Benefit Data: Extremely disturbingly, the leak could have included data regarding the employee's National Health Fund (NFZ) branch and information on alimony payments.
Possessing such a complete set of information by one person allows for the almost total takeover of the victim's digital life—from incurring financial obligations, through impersonating them in contacts with government offices, to taking over their internet accounts.
3. Domino Effect: One Attack, Entire Capital Group in Trouble
In the era of complex corporate structures, we often do not realize how interconnected different entities are. The attack on Dom Development perfectly illustrates that an incident in one company can have cascading consequences for the entire ecosystem of related firms. This is an important lesson not only for consumers but also for investors.
According to the official statement, the cyberattack concerned the entire Dom Development Group. This means that data processed by many different entities is at risk, including:
- Dom Development S.A.
- Dom Development Wrocław Sp. z o.o.
- Dom Development Kraków Sp. z o.o.
- Dom Development Kredyty Sp. z o.o.
- Dom Construction Sp. z o.o.
- Dom Development Grunty Sp. z o.o.
- Dom Land Sp. z o.o.
- Nasz Dom Foundation
- Euro Styl S.A.
Why is this so important? A client who dealt exclusively with "Dom Development Kredyty" might have been convinced that their data was processed only there. In reality, their information was located within a broader IT infrastructure that became the target of the attack. Such a "domino effect" is often the result of shared IT infrastructure, centralized databases, or joint data processing agreements within a capital group. One weak point can jeopardize the security of the whole.
4. Your Digital First Aid Kit: What to Do Here and Now?
Although the situation is serious, those affected by the leak are not defenseless. It is crucial to take immediate and conscious action to minimize the risk. Below is an action plan based on the company's recommendations and cybersecurity best practices.
- Immediately restrict your PESEL number. This is an absolute priority. The service is available free of charge in the mObywatel app. Restricting the PESEL number significantly hinders fraudsters from taking out loans, credits, or signing contracts using your data.
- Enable Two-Factor Authentication (2FA). Ensure you have active 2FA on all key online accounts, especially on your main email inbox. It is the gateway to resetting passwords for other services, and securing it is critical.
- Consider replacing your ID card. If you have a reasonable suspicion that your data, including the ID number and series, has been stolen, this is sufficient ground to apply for a new document.
- Monitor your credit activity. Create an account with the Credit Information Bureau (BIK) and activate alerts. You will receive a notification about every attempt to take out a loan in your name, allowing for a quick reaction.
- Be (even more) suspicious. Maintain heightened vigilance in the near future. Do not click on suspicious links, do not open attachments from unexpected emails, and verify the identity of callers asking for your data. Remember that fraudsters can use stolen information to lend credibility to their phishing attempts.
These actions are no longer extraordinary precautions, but the foundation of modern digital hygiene.
Conclusion: A Lesson We Didn't Want, But Must Learn
The data leak from Dom Development is a powerful reminder of several painful truths. First, our data has a much wider reach than we think, covering finances, assets, and—most disturbingly—our entire families. Second, it shows that even the biggest players on the market, to whom we entrust such sensitive information in the process of buying a home, can fall victim to an attack.
This incident is a bitter lesson about the price we pay for digital convenience. The question remains: as a society, are we ready to start treating our personal data with the same seriousness as the keys to our own home?
Aleksander
FAQ
How do I know if my data was leaked in this incident?
Dom Development has committed to directly informing individuals whose data may have been compromised. If you were a client, employee, or contractor of any of the group's companies, you should receive official notification. You can also contact the developer directly or check communications on their website in the privacy policy section.
What should I do first after learning about the leak?
Immediately restrict your PESEL number in the mObywatel app (free service). This is the most important security step to prevent financial obligations from being incurred using your data. Next, enable two-factor authentication (2FA) on all key accounts, especially your main email inbox, and create an account with the Credit Information Bureau (BIK) with alert activation.
Can I claim compensation from Dom Development?
Yes. Under GDPR (Article 82), you have the right to compensation for material and non-material damages resulting from a breach of personal data protection. To successfully claim compensation, you must demonstrate that you suffered actual damage (e.g., identity theft, financial losses) and that there is a causal link between the leak and the damage. It is advisable to consult with a lawyer specializing in personal data protection.
Sources:
About the Author
Dyrektor ds. Technologii w SecurHub.pl
Doktorant z zakresu neuronauki poznawczej. Psycholog i ekspert IT specjalizujący się w cyberbezpieczeństwie.
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