What is Data Loss Prevention? A Beginner’s Guide

October 16, 2025 By Nick Anderson No Comments 10 minutes

Data Loss Prevention (or just DLP for short) is a strategy and set of tools that help you keep sensitive data from ending up where it shouldn’t. DLP monitors how data moves – if the system sees something that breaks the rules, it can block the action and flag it for review. The goal of it is simple: make sure the right people access the right data for the right reasons.

Note: Data Loss Prevention, or DLP, keeps crucial information from getting stolen, leaked, or erased without permission. Newbies should know it tracks data while stored, active, or moving to block risks. FastestVPN supports this through encrypted links and safe remote entry.

What Does DLP Mean in Cybersecurity?

In cybersecurity, most defenses are designed to keep bad actors out. Data Loss Prevention (DLP) flips that – it’s about keeping your important data in.

DLP combines people, policies, and software to stop sensitive information from leaking. It monitors your data at every stage:

• Data in Use (like when someone copies files or screenshots confidential info).
• Data in Motion (such as emails or uploads moving across the network).
• Data at Rest (files sitting on servers or on employee laptops).

Let’s say someone tries to email a spreadsheet full of credit card numbers. A strong DLP in a security setup can catch that on the spot: recognize that pattern, stop the email, or encrypt it on the fly.

Types and Causes of Data Loss

Data loss usually falls into three main categories:

• A data breach happens when someone gets access to private information without permission. It’s the kind of scenario most people picture when they think of hacking – someone exploiting a weak spot in a system or forcing their way past a password to reach data they’re not supposed to reach.
• Data leakage is more accidental. It’s when sensitive data slips out because of a misconfiguration/poor security habits/human error.
• Then there’s data exfiltration, which is intentional theft. When someone (can be an outsider or insider) deliberately moves confidential data to a system they control. Every exfiltration involves a breach or a leak, but not every leak turns into theft.

These are broad categories, but if we get specific about how data loss actually happens, the list gets long fast. Sometimes, it’s something simple – a stray click that deletes a key file. In those cases, a good data recovery software tool can usually get it back in minutes. But other times, you’re looking at a full-blown incident with millions in damage and months of cleanup.

Here are some of the most common causes:

Human Error

This is one of the most common reasons data gets exposed. No bad intentions, just a lapse in attention. And that’s all it takes. It happens to the biggest corporations and home users alike.

It’s something most of us run into sooner or later. And more often than not, the cause isn’t a hacker or failing hardware, but a simple human mistake. According to a recent survey, around 34% of data loss incidents are caused by accidental human error (higher than hardware failure, which accounts for about 30%).

Human error is also what attackers often count on. Data thieves don’t always need to hack in; they just exploit human behavior. Through a quick phone call pretending to be tech support or via an infected USB drive they intentionally left for you to find, they rely on something called social engineering to trick people into handing over access.

Misconfigured Storage or Weak/Stolen Credentials

A surprising number of data leaks start with a simple mistake in cloud storage settings. 

Someone creates a folder in Google Drive or AWS and forgets to switch it to “private.” Suddenly, sensitive documents are exposed to anyone with the link (or worse, fully indexed by search engines).

This kind of misconfiguration doesn’t take skill to exploit. Attackers actively scan for open buckets and shared folders. Once they find one, they often grab everything before anyone notices.

Then there’s the credential problem. Weak passwords still show up in corporate environments more often than you’d think. Once an attacker logs in with valid credentials, they don’t trip alarms. They move quietly, pull files, and blend in with normal activity. Data loss protection tools can flag this kind of behavior (like mass downloads or unusual data transfers) before it escalates.

Phishing Attacks

This one’s a classic. Seemingly, everyone’s heard about it by now, but it continues to deliver results despite its age.

It typically starts with a deceptive email – one that looks like it came from your manager or some trusted service. It urges you to update a password or follow a link to a convincing (yet false) sign-in screen. A single click can then compromise your access details or introduce harmful software.

Even the most cautious users fall for it now and then. That’s why DLP tools often look for the effects of phishing – like unusual access patterns – so they can catch what simpler filters missed.

Insider Threats

Like we already mentioned, data loss often starts inside the company. Sometimes it’s human error. 

But other times, it’s someone copying client data before they leave – maybe to sell it, maybe to misuse it later.

Insiders already have access. They don’t need to break in or exploit anything. That makes them harder to spot. And they often stay hidden for a while. Recent studies show that in 2025, it took organizations an average of 172 days to identify a breach. That’s nearly six months where someone could quietly steal files without anyone noticing. And that number doesn’t even include containment. Once a breach gets discovered, it takes another 48 days on average to fully contain it. 

Types of Data Loss Prevention Controls

Now, let’s talk about how data loss prevention software helps you or your organization prevent all that and secure the data.

All DLP tools fall into three main categories, depending on where they focus their protection: Network, Endpoint, and Cloud.

Network DLP

Network DLP tools monitor your data while it moves across email, web traffic, file transfers, and other network channels. If someone tries to send a file filled with client details over Gmail or upload a confidential PDF to WeTransfer, Network DLP steps in – it can either block the action or alert the security team.

These tools inspect traffic in real time and are great at catching leaks before they leave your perimeter.

Popular Network DLP software includes:

• Forcepoint DLP – strong for regulated industries and advanced content inspection.
• Symantec DLP (Broadcom)  – deep network integration and policy controls.
• Cisco Secure DLP – designed for enterprises already using Cisco’s security stack.

Endpoint DLP

If Network DLP keeps an eye on data as it moves across your systems. Endpoint DLP – focuses on local activity. If someone saves files to a USB stick, prints out sensitive documents, takes screenshots, or syncs folders to a personal cloud account, it’s built to notice that kind of behavior and step in if needed.

Endpoint tools are critical in remote work setups where employees might be off-network but still have access to company data.

Examples of Endpoint data loss prevention tools:

• Digital Guardian DLP is a strong option for intellectual property protection and insider threats.
• Microsoft Purview Data Loss Prevention covers both endpoint and Microsoft 365 cloud environments.
• Trellix (formerly McAfee) DLP Endpoint combines device-level monitoring with central policy management.

Cloud DLP

And of course, there’s Cloud DLP – the part that watches over your data once it’s in the cloud. With so many companies relying on Google Workspace, Microsoft 365, Dropbox, and other SaaS tools, this layer has become just as important as network or device-level protection.

Cloud DLP helps you spot and stop risky behavior inside cloud apps. Let’s say someone creates a Google Doc containing customer credit card info and shares it with “Anyone with the link.” That’s a problem. Cloud DLP can flag it instantly, restrict access, and alert your admin.

Top Cloud DLP solutions:

• Google Workspace DLP is built into the Google Admin Console (easy to set up for Gmail or Drive).
• Microsoft Purview (formerly Compliance Center) has broad policy controls across SharePoint, OneDrive, Teams, and Exchange.
• Proofpoint Cloud App Security Broker (CASB) is strong at managing DLP across multiple cloud platforms and has rich reporting.

It’s rare that one type of data leakage prevention covers everything. A startup might start with Cloud DLP if it relies heavily on Google Workspace. But larger organizations usually run all three together.

Best Practices and Tips for Making DLP Work

Don’t expect that once you set up the software, you’ll instantly reap all the data loss prevention benefits with no extra effort. There’s a lot more that goes into it; DLP works best when it’s part of a broader process: you need the right policies, the right people, and again, the right strategy that evolves over time. 

Here are some best practices that help make it all actually work:

• The first thing we want to list is: know what data you’re protecting. Start with your most sensitive or regulated data – things like customer info, financial records, IP. Don’t try to secure everything at once. Prioritize.
• Next: map where that data lives. Identify which devices, apps, and services store or process it. You can’t protect what you haven’t located. DLP doesn’t work well if it’s flying blind.
• Use monitor mode first. Before you block anything, run DLP in detection-only mode. Watch what gets flagged and adjust your rules. Most DLP platforms let you run in “monitor only” mode at the start – and that’s the smart move. This lets you see what your rules would catch without stopping anything. You can learn where your sensitive data flows, how users interact with it, and which alerts are noise vs. real problems. It also gives you time to fine-tune policies before they start interrupting workflows.
• Speaking of policies: fine-tune them. Overly aggressive policies will annoy people and lead to workarounds. Start narrow, then expand coverage.
• Get leadership and key teams involved early. DLP isn’t something IT can handle alone. If your policies affect how people work (or how you monitor what they do), you’ll need buy-in from leadership, legal, HR, and compliance teams. When everyone understands why DLP is in place and how it helps the business, adoption goes a lot smoother.
• Train your users. As we said earlier, most data leaks happen because someone didn’t know better. Make sure people understand what triggers alerts and why it matters.

Final Tips

And finally, we want to say this: DLP is not set-it-and-forget-it. You’ll need to update it as your environment, risks, and tools evolve. New apps get introduced. Teams shift how they work. Sensitive data shows up in new places.

Every few months, revisit your policies. Add new coverage if needed. Retire outdated rules. Review how users interact with alerts, and adjust to reduce friction. A good DLP is never static; it keeps up with your organization.

Think of it as maintenance. Micromanagement is the last thing you want. When DLP becomes too rigid, it starts to enjoy the people it’s supposed to protect.

There are plenty of stories out there about security tools backfiring because they got in the way of real work. You still want to reduce risk, but without slowing everyone down.

Talk to the teams using the data. If sales need USB access at trade shows, don’t ban it entirely – set up exceptions for approved devices with extra logging. If marketing needs to send large files externally, give them a secure way to do it.

Because the true DLP meaning is about protecting sensitive data without breaking the way people work.