Data leakage – What it is, how it happens, how to check and where to report it

Data leaks have become one of the biggest challenges of modern business. In 2023, the average cost of a single incident exceeded $4.45 million, and the time required to detect and contain a leak extended to 277 days. However, in addition to the immediate financial losses, organizations face the long-term consequences of loss of customer trust and potential regulatory penalties.

In this comprehensive guide, cybersecurity experts examine all key aspects of data leaks. We present a comprehensive approach to the problem – from understanding leakage mechanisms, to detection and response methods, to prevention and risk minimization strategies. Special attention is paid to practical tips and best practices that will enable organizations to more effectively protect themselves from data leaks and meet legal and regulatory requirements.

Whether you’re a security professional, IT manager or board member responsible for protecting your organization’s data, you’ll find concrete solutions and recommendations backed by the latest industry research and statistics. Learn a comprehensive approach to data leakage and how to effectively protect your organization from this growing threat.

What is a data leak?

A data leak is a security incident in which confidential, protected or sensitive information is exposed to unauthorized individuals or systems. Contrary to popular belief, not every data leak is the result of a cyber attack – it can also occur as a result of human error, misconfiguration of systems or procedural negligence.

According to a recent IBM Security study, the average cost of a data leak in 2023 was $4.45 million globally. What’s more, it takes organizations an average of 277 days to identify and stop a data leak. This statistic shows how important it is to implement appropriate mechanisms for monitoring and responding to security incidents.

Data leakage can take many forms – from accidentally sending a document to the wrong recipient, to unsecured databases publicly available on the Internet, to malicious actions by employees or sophisticated hacking attacks. It is crucial to understand that leaks can involve digital data as well as physical documents.

In the legal context, it is particularly important to distinguish between a simple data leak and a data breach under the RODO. The latter is subject to specific regulations and requires specific actions on the part of the data controller, including a potential notification to the supervisory authority.

What is the difference between a data leak and a data breach?

Although the terms “data leak” and “data breach” are often used interchangeably, there are important legal and technical differences between them. A data breach is a broader term that encompasses any event leading to the accidental or unlawful destruction, loss, modification, unauthorized disclosure of or access to personal data.

In practice, this means that any leakage of personal data is a breach, but not every breach involves a leak. For example, ransomware encrypting data without exfiltrating it is a breach of data availability, but not necessarily a data leak. According to statistics from the DPA, more than 12,000 data protection violations were reported in 2023, of which about 40% were actual data leaks.

The scope of responsibility and required actions is also an important difference. In the event of a data breach, the controller has a legal obligation to conduct a detailed risk analysis and potentially notify both the supervisory authority and data subjects. A data leak not subject to the RODO may not require such actions, although good business practices often suggest a similar approach.

Technically, a breach can also include situations of temporary data unavailability or loss of integrity, while a leak always involves compromising the confidentiality of information. This distinction is crucial when planning incident responses and implementing security mechanisms.

What are the most common causes of data leakage?

According to recent industry research, human error remains the leading cause of data leaks, accounting for about 82% of all incidents. This ranges from inadvertent actions, such as accidentally sending documents to the wrong recipients, to knowingly violating security procedures to “make things easier” for oneself.

The second most common cause is configuration errors in systems and applications. Particularly dangerous are poorly secured cloud databases and S3 buckets, which regularly lead to massive data leaks. According to the Verizon Data Breach Investigations Report, improper cloud configuration is responsible for 14% of all data leaks in corporate environments.

Hacking attacks, contrary to popular belief, are only in third place. Particularly dangerous are attacks using phishing and social engineering techniques, which often lead to the hijacking of users with high privileges. Statistics show that about 36% of all data leaks related to cyber attacks begin with a successful phishing attack.

Malicious employees (insider threats) are also becoming a growing problem. Studies show that about 60% of departing employees take company data with them, often unknowingly violating security policies and regulations. Even worse, 25% of them admit to intentionally taking out information that may be useful in their new job.

What types of data are most often leaked?

Personal data is the most commonly compromised category of information, with basic identifying information like names, email addresses and phone numbers being particularly vulnerable. According to a report by the Identity Theft Resource Center, in 2023 this type of data accounted for more than 73% of all leaks. This high percentage is due to the fact that virtually every organization processes this information, and its value on the black market remains steadily high.

The second most commonly stolen type of data is credentials – passwords, access tokens and API keys. Compromising them is particularly dangerous, as it often leads to cascading security breaches. Studies show that the average user uses the same password for about 40% of their accounts, making it likely that a leak of login data from one service can lead to the compromise of many others.

Financial data, including credit card numbers, bank account data or transaction information, ranks third in terms of frequency of leaks. Although they are usually better protected than master data, their high market value makes cybercriminals willing to devote more resources to acquiring them. Statistics show that the average time from the leak of credit card data to the first attempt to use it illegally is only 24 hours.

Leaks of medical data and health information are also increasingly common. This type of data is particularly valuable to criminals because of its potential to be used for blackmail or extortion. In 2023, there was a 40% increase in medical data leaks compared to the previous year, making it the fastest-growing category in terms of the number of incidents.

How can data leakage occur?

Unauthorized access to IT systems remains a major vector for data leakage. Attackers use a variety of techniques, from simple brute force attacks, to exploitation of known vulnerabilities, to advanced attacks using zero-day exploits. According to ENISA, in 2023, more than 45% of all data leaks occurred through this route.

Phishing and social engineering are the second most popular vectors for data leakage. Criminals are improving their techniques, using artificial intelligence to create more convincing messages and better target potential victims. Spear phishing targeting high-level employees is particularly dangerous – according to recent studies, the probability of success of such an attack is as high as 65%.

Accidental sharing of data by employees is the third most common cause of leaks. This includes both improper permission settings in cloud systems and unknowingly sending confidential information to the wrong recipients. In 2023, it was reported that the average organization experiences about 260 incidents of accidental sharing of confidential data per month, of which about 20% represent a potential risk of a serious security breach.

Malware, especially data exfiltration ransomware (double-extortion ransomware), is a growing threat. Criminals not only encrypt data, but also steal it before encryption, increasing the pressure on victims. Statistics show that in 2023, 70% of ransomware attacks included a data exfiltration component, up 30% from the previous year.

How do I check if my data has been leaked?

Verifying a potential data leak requires a systematic approach and the use of a variety of monitoring tools. A basic step is to regularly check specialized data leak monitoring services, such as Have I Been Pwned or BreachAlarm. Studies show that users who regularly monitor their online data have a 47% greater chance of detecting the compromise of their information early.

Organizations should implement advanced dark web monitoring systems that automatically scan hacker forums and marketplaces for signs of leaked corporate data. According to analysis, the average time between the appearance of stolen data on the dark web and its use by criminals is about 76 hours, highlighting the importance of quick detection.

Another important element is monitoring network traffic for abnormal data transmission patterns. SIEM (Security Information and Event Management) systems can detect anomalies that indicate potential data exfiltration. Statistics show that organizations using advanced SIEM systems detect data leaks 219 days faster on average than those relying on basic monitoring alone.

Regular auditing of permissions and access to IT systems can reveal unauthorized changes indicating data compromise. In 2023, as many as 34% of detected data leaks were identified just during routine privilege reviews. This process should include both local systems and cloud services.

What to do if a data leak is detected?

Immediate response to a detected data leak is key to minimizing potential damage. The first step should be the creation of an incident response team to coordinate all recovery efforts. According to research, organizations with a dedicated CERT/CSIRT team reduce the average cost of a data leak by 35% compared to companies without such structures.

Documenting and securing digital evidence must begin as soon as possible after an incident is detected. This includes taking forensic images of systems, securing logs and documenting the chronology of events. Practice shows that about 67% of legal cases involving data leaks fail due to insufficient or improperly secured evidence documentation.

Conducting a detailed analysis of the scope of the leak is essential to determine the scale of the incident and the potential impact on the organization. It is necessary to determine exactly what data has been compromised, who is affected, and what the consequences of its disclosure may be. Studies show that on average organizations take 73 days to fully determine the scope of a data leak, which significantly affects the effectiveness of remediation efforts.

After the initial analysis, it is necessary to implement immediate countermeasures, such as changing passwords, revoking certificates and blocking compromised accounts. In the case of 45% of data leaks, quick remedial actions made it possible to significantly reduce the extent of the compromise and prevent secondary security incidents.

Where should I report leaked personal information?

Reporting a personal data leak is subject to strict regulations, and the main addressee of such notification is the Office for Personal Data Protection (OPA). A data controller is obliged to notify the supervisory authority within 72 hours of discovering a breach, as long as the breach is likely to result in a risk of violating the rights or freedoms of individuals. Statistics from the DPA show that in 2023 only 62% of breach notifications were made within the required time.

In the case of incidents involving public sector entities or critical infrastructure operators, it is also necessary to notify the NASK CSIRT (National Cyber Security Center). Data shows that coordination between the DPA and the NASK CSIRT allows for more efficient incident management – the average response time is reduced by 40% compared to cases reported to only one authority.

Organizations operating in the financial sector have an additional obligation to report leaks to the Financial Supervisory Commission (FSC). This is especially true for banks, insurance companies and other financial institutions. According to the FSC, 2023 saw a 75% increase in the number of security incident reports in the financial sector compared to the previous year.

If the leak involves telecommunications data, the Office of Electronic Communications (UKE) should also be notified. In the case of telecom operators, statistics show that about 30% of all data leaks are related to errors in billing systems or customer databases, which requires special attention from the regulator.

At what time should data leakage be reported?

A key deadline under RODO is the 72-hour period for reporting a breach to the supervisory authority, calculated from the moment the breach is discovered. It is worth emphasizing that it is not the moment when the leak actually occurs, but the moment when the organization detects it. Studies show that organizations that have implemented automated incident detection systems are able to meet this deadline in 85% of cases.

Additional, often shorter notification deadlines apply for certain economic sectors. For example, banks must inform the FSC of major security incidents within 24 hours. Statistics show that in 2023, only 45% of financial institutions were able to meet this deadline, demonstrating the magnitude of the challenge in responding quickly to incidents.

In the event of a high risk of violation of the rights or freedoms of individuals, the controller is required to notify data subjects “without undue delay.” Practice shows that organizations need an average of 5 days to prepare and start the process of notifying the affected, which is often criticized as too long.

A delay in reporting a breach must be duly justified. The research indicates that the most common reasons for exceeding the 72-hour deadline are the complexity of the incident (43% of cases), difficulties in determining the scope of the breach (38%), and problems with coordination between different departments of the organization (19%).

Who is responsible for reporting a data leak?

The primary responsibility for reporting a data leak lies with the data controller, that is, the entity that alone or jointly with others determines the purposes and means of data processing. In practice, this means that in business organizations this responsibility lies with the board of directors, which should ensure that adequate procedures and resources are in place to handle such incidents. Studies show that companies where the board of directors is actively involved in cyber security issues record 35% fewer serious incidents.

The Data Protection Officer (DPO), if appointed in the organization, plays a key advisory role in the breach notification process. His or her responsibilities include assisting the administrator in assessing the risks associated with a breach and preparing appropriate documentation. Statistics from the DPA show that organizations with an IOD respond 40% faster on average to data leakage incidents.

In the case of processors (processors), they are obliged to immediately notify the administrator of a detected breach. Practice shows that the average time between the processor’s detection of a breach and the administrator’s notification is 24 hours, although shorter deadlines are often set in entrustment agreements. According to industry research, delays in communication between processors and administrators account for 28% of cases where the statutory 72-hour deadline for breach notification is exceeded.

In multi-branch or multinational organizations, it is crucial to clearly define roles and responsibilities for breach reporting. Experience shows that companies with a centralized security incident management system are 55% more effective in coordinating their response to a data leak, especially when the incident affects multiple jurisdictions.

How to protect against data leakage?

Implementing a comprehensive data protection strategy requires a multi-layered approach, starting with proper classification of information. Organizations that have conducted a thorough inventory and classification of data reduce the risk of major leaks by 63% compared to companies without such practices. The classification process should be updated regularly, taking into account changing business needs and new types of data being processed.

Encryption of sensitive data, both at rest and during transmission, is a fundamental layer of protection. According to a recent study, organizations using advanced cryptographic solutions and proper key management reduce the average cost of a potential data leak by 42%. It is particularly important to use end-to-end encryption for the most sensitive data and to rotate encryption keys regularly.

Access control based on the Principle of Least Privilege significantly reduces the potential scope of a data leak. Statistics show that 65% of major data leaks involve excessive user privileges. Implementing an identity and access management (IAM) system with automatic verification and revocation of privileges reduces the risk of internal leaks by 76%.

Regular employee training in information security is key to minimizing the risk of data leakage. Organizations that conduct systematic awareness programs that include hands-on exercises and phishing simulations report 47% fewer incidents related to human error. Training that uses real-world examples of incidents and personalized threat scenarios is proving particularly effective.

What are the consequences of data leakage?

The consequences of a data leak are multifaceted and often long-term, going well beyond immediate financial losses. According to a study by the Ponemon Institute, the average total cost of a data leak for a large organization in 2023 was $4.45 million. Importantly, this figure takes into account not only the immediate costs associated with incident response, but also the long-term reputational and operational impacts.

Loss of customer trust is one of the most serious consequences of a data leak. Studies show that 65% of consumers lose trust in organizations after a major data leak, and 85% of them share their negative experiences with at least ten other people. As a result, companies experience an average 3.9% drop in stock value in the first 14 days after a leak is revealed, and it can take up to 24 months to fully rebuild a reputation.

Administrative penalties imposed by supervisory authorities can be particularly severe, especially in the context of RODO violations. In 2023, the total value of fines imposed in the EU for data protection violations exceeded €1.7 billion. It is worth noting that the amount of fines does not depend solely on the scale of the leak, but also on how the organization prepared for data protection and responded to the incident. Companies that could prove the implementation of adequate security measures before the leak received on average 40% lower fines.

Operational costs for handling the aftermath of a leak often exceed original estimates. These include spending on digital forensics (an average of $385 per hour for a specialist), notifying victims ($14 per person), providing credit monitoring ($40 per year per person) and strengthening security systems. In addition, organizations often face legal and PR costs, which can run into the millions of dollars in the case of major leaks.

How do you recognize that a data leak has occurred?

Early detection of a data leak requires systematic monitoring of multiple indicators and anomalies in IT systems. Unusual patterns in network traffic, especially large data transfers at unusual times or to unknown locations, can be the first warning sign. Analysis of system logs shows that 76% of data leakage cases had previously had unusual network traffic patterns that could have been detected with proper monitoring.

Unauthorized changes in user privileges or sudden modifications to databases should arouse the security team’s immediate vigilance. Statistics show that in 45% of data leaks, they were preceded by suspicious changes in permissions that were not noticed or verified in time. SIEM systems configured to detect such anomalies increase the chance of early incident detection by 68%.

Unusual user behavior, such as logging in at unusual times, accessing rarely used resources or downloading documents en masse, can signal a potential leak. Organizations using sophisticated User Behavior Analytics (UBA) systems are able to detect suspicious activity an average of 27 days earlier than those relying on traditional monitoring.

External signals, such as the appearance of an organization’s data on the dark web or an unusual increase in the number of login attempts to systems, can also indicate a leak. According to the study, it takes an average of 197 days from the time of a leak to its detection in organizations that do not have sophisticated dark web monitoring and threat analytics systems.

What tools help detect data leakage?

Security Information and Event Management (SIEM) systems are an essential tool in the arsenal of security teams, aggregating and analyzing logs from various sources in real time. Advanced SIEM implementations using machine learning can detect subtle anomalies indicating potential data leakage. Organizations’ experience shows that a properly configured SIEM system can reduce leak detection time by up to 71% compared to traditional monitoring methods.

Data Loss Prevention (DLP) solutions act as gatekeepers for sensitive data, monitoring and controlling its flow within an organization’s network. Modern DLP systems use advanced algorithms to identify and classify sensitive information, blocking unauthorized attempts to exfiltrate it. Statistics show that organizations using next-generation DLP solutions are able to prevent 82% of inadvertent data leaks by employees.

Dark web monitoring tools are becoming an increasingly important part of leak detection strategies. Automated scanners scour hacker forums, marketplaces and criminals’ communication channels for signs of stolen data. Research shows that organizations using professional dark web monitoring services detect leaks 47 days earlier on average than those relying solely on internal detection mechanisms.

UEBA (User and Entity Behavior Analytics) systems use advanced analytics to profile normal user and system behavior, enabling the detection of deviations that could indicate a leak. In practice, organizations using UEBA experience 56% fewer false alarms compared to traditional anomaly detection systems, with a 34% increase in actual incident detection.

How to conduct a quick identification of the cause of the leak?

A methodical approach to incident analysis begins with securing digital evidence and creating a timeline of events. It is crucial to use digital forensics tools to reconstruct the sequence of activities leading up to the leak without compromising the integrity of the evidence. The experience of CERT teams shows that organizations using standard digital forensics procedures identify the source of a leak 43% faster on average than those operating ad hoc.

Analysis of system and network logs should focus on identifying the starting point of compromise (patient zero). Log visualization and network analytics tools help quickly catch anomalies and links between seemingly unrelated events. Statistics show that using advanced log analysis tools reduces the time to identify the cause of a leak by an average of 56 hours.

By correlating data from various sources, including security systems, applications and infrastructure, a complete picture of an incident can be created. SOAR (Security Orchestration, Automation and Response) platforms automate the process of data collection and analysis, speeding up the identification of the cause of a leak. Organizations using SOAR reduce the average incident response time by 78% compared to manual analysis.

Threat Intelligence provides the context necessary to understand the nature of the attack and potential perpetrators. Analysis of indicators of compromise (IoC) combined with data on known techniques, tactics and procedures (TTP) of criminal groups allows for faster identification of the method of leakage. Research shows that organizations actively using threat intelligence are able to determine the cause of a leak an average of 12 days faster than those relying solely on internal analysis.

Summary

To summarize the above chapters, it is worth highlighting some key aspects related to data leaks that every organization should consider in its cyber security strategy.

Above all, data leakage is not just a technical problem, but a complex organizational challenge requiring a holistic approach. Effective protection against leaks requires a combination of appropriate technology, procedures and employee training. It is especially important to understand that even the best technical safeguards can fail if the organization does not ensure an adequate security culture.

From a legal and regulatory perspective, it is crucial for organizations to be prepared to meet breach reporting requirements. The 72-hour deadline for reporting a leak to the DPA may seem long, but practice shows that without proper preparation and tested procedures, meeting this deadline is a major challenge. Organizations should regularly test their incident response procedures through exercises and simulations.

In terms of tools and technologies, it is worth noting the growing importance of solutions using artificial intelligence and machine learning in detecting potential leaks. Next-generation SIEM systems, advanced DLP or SOAR platforms not only increase the effectiveness of incident detection, but also significantly reduce the number of false alarms, allowing security teams to focus on real threats.

Finally, the importance of a proactive approach to data security cannot be overstated. Regular audits, penetration testing, bug bounty programs or continuous threat monitoring can identify and eliminate potential security vulnerabilities before they are exploited by attackers. Investing in prevention is always more cost-effective than incurring the costs of an actual data leak.

Organizations that treat data security as an ongoing process rather than a one-time project are much better prepared for today’s threats. The key to success is to build an organizational culture in which every employee understands his or her role in protecting data and can respond appropriately to potential security incidents.

Keep in mind that in today’s increasingly digital world, data leakage can have disastrous consequences not only for the organization, but most importantly for the individuals whose data has been compromised. That is why it is so important to treat data protection as one of the fundamental priorities in any organization’s strategy.

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About the author:
Marcin Godula

Marcin is a seasoned IT professional with over 20 years of experience. He focuses on market trend analysis, strategic planning, and developing innovative technology solutions. His expertise is backed by numerous technical and sales certifications from leading IT vendors, providing him with a deep understanding of both technological and business aspects.

In his work, Marcin is guided by values such as partnership, honesty, and agility. His approach to technology development is based on practical experience and continuous process improvement. He is known for his enthusiastic application of the kaizen philosophy, resulting in constant improvements and delivering increasing value in IT projects.

Marcin is particularly interested in automation and the implementation of GenAI in business. Additionally, he delves into cybersecurity, focusing on innovative methods of protecting IT infrastructure from threats. In the infrastructure area, he explores opportunities to optimize data centers, increase energy efficiency, and implement advanced networking solutions.

He actively engages in the analysis of new technologies, sharing his knowledge through publications and industry presentations. He believes that the key to success in IT is combining technological innovation with practical business needs, while maintaining the highest standards of security and infrastructure performance.

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