What is Data Loss Prevention? | A Complete Guide to DLP Security

Data is the most valuable asset today’s businesses possess – and volumes are growing all the time. According to Statista, there were 120 zettabytes of digital information in use worldwide at the start of 2024, but this is set to reach 181 zettabytes by the end of 2025. Within this will be a wide range of highly sensitive details, from customer personal and financial information to trade secrets and other vital enterprise intellectual property.

It’s therefore vital that all companies make protecting this data their highest priority. Data loss – whether accidental or as the result of criminal activity – can be hugely damaging to businesses. As well as the financial impact, the reputational damage caused by failing to protect sensitive data can last for many years.

To avoid this, firms must have a clear data loss prevention (DLP) strategy in place that covers every aspect of their operations. Understanding what is required and the technology necessary to implement this is essential in keeping information safe in a highly challenging environment.

Data loss prevention refers to the tools, technologies and processes needed to prevent the loss or exposure of information. It aims to prevent the inappropriate access, use, sharing or exfiltration of data both within and outside the organization.

Some of the most common causes of data loss that an effective DLP strategy can address include:

Data exfiltration: The deliberate theft of data by external hackers is now a common goal of any ransomware attack, with more than nine out of ten such incidents aiming to exfiltrate data. This can then be used to extort money from the organization by threatening to publicly release sensitive files until the company pays.

Insider threats: Employees with a grievance against their firm may copy and remove data for a number of reasons. They may look to take company secrets to a new employer and seek to sell it to the highest bidder, or simply cause harm in retaliation for a perceived wrong. Such incidents can be particularly hard to spot if an individual has legitimate access to the data in question.

Negligence: Careless employee behavior that leads to data leaks can range from leaving company devices on a train to accidentally emailing documents to the wrong recipient. It can also cover falling victim to phishing scams where hackers pose as senior executives and request information.

The biggest risks of data loss are financial. According to IBM, for instance, the average cost of a data breach in 2024 now stands at $4.88 million, marking a ten percent increase on 2023.

For business in heavily regulated industries, the effects can be even more severe. For example, healthcare organizations that are subject to HIPAA are especially vulnerable due to the sensitive nature of the data they possess and the large regulatory penalties for failures. IBM’s research found these companies faced the highest costs of any sector, with average data breach expenses reaching $9.77 million.

Other industries at high risk include financial services, technology firms and the energy sector, but every firm is vulnerable to the threat of data loss. Almost every business will deal with some form of personally identifiable information (PII) that will be of value to hackers and regulations such as GDPR can result in large fines for the exposure of such data.

There are several types of DLP available that focus on data in various areas of the network and at different times. In order to implement a comprehensive solution, it’s important that cybersecurity teams are familiar with all of these and where they should be applied.

Key areas that must be taken into account when developing a DLP plan include the following:

• Network DLP: This covers data at rest and in motion throughout the network and involves monitoring systems, identifying who is accessing what data, tracing it to see where it is being sent within the network and helping security teams understand where data is at any given moment.
• Endpoint DLP: Endpoint DLP focuses on the range of servers, cloud tools, PC, laptops, mobile devices or other endpoints that have access to the network. It tracks when data is moved to these devices and enters or leaves the network in order to spot any suspicious data exfiltration attempts.

• Cloud DLP: Cloud DLP covers aspects of the above two areas, but is more specialized to tackle the unique challenges of cloud computing, which will typically require large quantities of data to be stored outside the network perimeter. This closely monitors how this data is protected both when stored on cloud servers and when it is moved back into and out of the network.

Data loss prevention is a wide-ranging term that incorporates people, processes and technology. It works by analyzing activity within a business to identify and alert security teams to suspicious behavior. This can include repeated attempts to access data, unusual working patterns and suspicious network traffic. To be effective, tools must be able to understand the context of how data is being used and enforce policies that have been defined by the business.

In order to put these principles into practice, there are a range of tools and technologies that should be used. Some of the most important elements that should not be overlooked in any DLP strategy include the following:

Encryption: An essential tool for protecting data both in rest and in motion, though encryption measures ensure that authorized users will be able to view data.

Access management: A comprehensive access management program should cover several aspects, including multifactor authentication, principles of least privilege to ensure users can only view data that is relevant to their tasks, and monitoring that can automatically send an alert when suspicious login attempts are made.

Employee training: Regular reminders of employees’ responsibilities when it comes to data protection are important, as are sessions to help them spot common ransomware attacks such as phishing attempts.

Endpoint protection: Guarding endpoints is one of the most critical aspects of a DLP strategy, but this is about more than preventing hackers getting into the network. With the right tools, any attempts to exfiltrate data from a network can be detected and prevented quickly.

Implementing a comprehensive data loss prevention strategy is easier said than done. One of the biggest challenges is the scale of modern business networks. With vast amounts of data being accessed from potentially tens of thousands of endpoints – many of which may be invisible to IT teams – it can be hugely challenging to bring networks under control.

Another issue is striking the right balance between security and usability. While tools such as encryption, access management and anti data exfiltration technology are vital, care must be taken not to disrupt day-to-day operations.,

For example, automation should be used to shut down any data theft attempts before they have a chance to succeed, as waiting for manual human intervention will be too slow. However, false positives that block legitimate traffic can be very frustrating to users. Therefore, it’s important to have intelligent tools that are able to more accurately differentiate between genuine and suspicious activity.

Simply having the right tools and technologies in place is not enough to guarantee protection against today’s complex and evolving threats. Following these best practices will be crucial in ensuring that any DLP strategy is implemented effectively. 

Have a complete picture of your data: Firms can’t protect what they can’t see, so it’s vital that there is a full audit of data to identify what information the business possesses, where it is stored and which pieces should be the highest priority for protection.

Ensure everyone takes responsibility: Data protection isn’t just the responsibility of the cybersecurity team – it’s up to everyone to play their part. Staff training must emphasize this as a priority. 

Regularly review and update tools and processes: Good patch management is an important part of keeping systems secure, as hackers are always looking to exploit as-yet undetected vulnerabilities to steal data. However, efforts shouldn’t stop there, as firms always need to be aware of the latest developments in the sector and have the most up-to-date DLP technologies in order to counter the constantly-evolving tactics of criminals. 

Ensure every endpoint is accounted for: Keeping every endpoint under control becomes increasingly difficult as more devices are added to the network and trends such as remote and hybrid working introduce consumer-grade, personally-owned items to the mix. It’s therefore important IT teams have full visibility into every device and are able to install effective software onto them.

Test systems regularly: Regularly reviewing the capabilities of the firm’s defenses can help stop any gaps, particularly those that might be introduced when new tools are added to the network. This includes techniques such as penetration testing and phishing tests, where employees are sent fake phishing emails to see how they respond.

With cybercriminals continuing to evolve their tactics, and trends towards double and even triple extortion ransomware showing no signs of slowing down, it will be critical that firms improve their DLP solutions in order to keep up.

Traditional endpoint protection solutions that mainly focus on stopping hackers getting in are no longer enough. In today’s environment, businesses have to assume they have already been breached, so the focus must shift to preventing hackers leaving the network with their prize. This means specialist capabilities such as anti data exfiltration (ADX) will be essential.

At the same time, the use of technology, such as artificial intelligence and automation to study data patterns, learn what normal behavior looks like and step in without human intervention, will be important in ensuring data can be protected without delays, while not disrupting legitimate traffic.