GDPR perspective: Why hacker invoices are also a data protection problem

What the GDPR really protects

The General Data Protection Regulation (GDPR) was created to protect the personal data of people in the EU. Personal data is broadly defined and includes all information relating to an identified or identifiable person.

When hackers break into a company's email system to inject fake invoices, they almost always gain access to other data as well. Communication histories, contact details, and payment information usually contain personal data. Once this data is compromised, the GDPR comes into play.

Hacker invoices as a gateway

Fake invoices are rarely isolated incidents. They are usually part of larger social engineering attacks. Hackers use phishing to gain access to email accounts and then send seemingly genuine invoices on behalf of suppliers or executives.

In this way, they not only manipulate financial processes, but also gain access to contracts, internal communications, and business processes – often containing personal data of customers, partners, or employees.

Real-life example: German company transfers money to fraudsters

In the summer of 2025, Security Insider reported on a case in which a German company transferred money to fraudsters instead of the actual construction company after a hacker attack (source).

The financial loss was high, but the data protection implications were also significant. The attackers had access to confidential email correspondence, project data, and possibly personal information about employees and subcontractors. This case shows how closely financial and data protection risks are linked.

Reporting obligation (72-hour rule)

According to Article 33 of the GDPR, companies must report data breaches to the competent supervisory authority within 72 hours. Even if the incident appears to be a mere billing problem, the compromised email account indicates possible data access.

Liability and fines

The GDPR provides for penalties of up to €20 million or 4 percent of global annual turnover, whichever is higher. If a company cannot prove that sufficient protective measures are in place, it faces severe sanctions.

Documentation requirement

Companies are required to document all security incidents. Incomplete documentation exacerbates the situation and makes it more difficult to provide evidence in the event of an audit.

Awareness training for employees

Employees are the first line of defense. Many fraudulent invoices begin with phishing. Training ensures that invoices are checked before payments are released.

Key training content:

• Recognizing phishing indicators in emails
• Checking bank details before transfers
• Reporting suspicious invoices to IT or compliance

Technical security measures

• Multi-factor authentication (MFA): prevents unauthorized access to email systems
• Encryption of emails and files: protects against interception of data
• Zero-trust approach: strict access control based on the principle of least privilege
• SIEM and monitoring systems: detect suspicious activities and patterns

Compliance tools and monitoring

Modern compliance solutions such as heyData help to bring data protection processes into line with the GDPR. They provide support for:

• Automated documentation
• Standardized reporting processes
• Risk analyses and gap assessments
• Continuous monitoring

Many companies view hacking as purely a financial or IT problem. This is a dangerous misconception. Reasons for this:

• Financial damage and data theft often occur simultaneously
• Regulatory authorities do not distinguish between “primary” and “secondary” data leaks
• Customers and partners expect transparency when it comes to handling data

Those who do not also see hacker bills as a GDPR problem risk legal consequences and a loss of trust.

Are hacker invoices automatically a GDPR violation?
Not necessarily. However, as soon as personal data is affected, it constitutes a data protection violation.

Do I have to report a fake invoice to the supervisory authority?
Yes, if the incident involves data access or data loss.

What is the deadline for reporting?
72 hours after the incident becomes known.

How can I protect my company?
Through a combination of strong IT security, continuous awareness training, and compliance measures.

Can I also be punished if no personal data is involved?
No. However, if personal data is later proven to be involved and the incident is not reported, the penalties will be even higher.

• Stop payment immediately and inform your bank.
• Analyze the incident—was personal data accessed?
• Notify the supervisory authority within 72 hours if data is affected.
• Notify affected customers or employees.
• Carefully document each step.
• Review and improve security measures.

Hacker bills are much more than just a nuisance for accounting departments. They are a gateway for data breaches and therefore a serious GDPR problem. Companies that underestimate this risk themselves high fines, legal risks, and a loss of trust.

The good news is that the risk can be significantly reduced with a combination of employee training, technical protective measures, and compliance monitoring. The GDPR is not just a mandatory program, but a framework for greater resilience against modern cyberattacks.