Data Loss Prevention (DLP)

Data Loss Prevention (DLP) is an in-demand cybersecurity strategy that detects and prevents unauthorised access, sharing, or transmission of sensitive organisational data through a combination of technologies, policies, and processes. Unlike traditional perimeter-based security, DLP focuses on protecting data itself by monitoring how users interact with sensitive information across email, cloud applications, and endpoints.

DLP products use business rules to classify and protect confidential and critical information so that unauthorised users cannot accidentally or maliciously share or leak data, putting the organisation at risk. For example, if an employee tried to forward a business email outside the corporate domain or upload a corporate file to a cloud storage service like Dropbox, the employee would be denied permission. DLP security monitors data across three critical states: data at rest (stored files), data in motion (information being transmitted), and data in use (active content being accessed or modified).

The urgency for proven data loss prevention solutions has never been greater. The global DLP market is projected to grow from $2.58 billion in 2024 to $12.29 billion by 2033, reflecting an 18.9% compound annual growth rate. Organisations are adopting DLP primarily due to increased insider threats and rigorous data privacy laws, many of which have stringent data protection or access requirements.

With the average cost of a data breach reaching $4.4 million in 2025, DLP has evolved from optional security to essential business infrastructure. In addition to monitoring and controlling endpoint activities, some DLP tools can also be used to filter data streams on the corporate network and protect data in motion.

“The ever-growing universe of cloud applications continues to expand the risk surface to an organisation,” warns Sumit Dhawan, Proofpoint CEO. “This exposure applies not only to corporate-approved applications like M365 but also to unapproved apps such as cloud file sharing,” he adds.

With 2 out of 3 organisations experiencing “significant data loss” in the past year, investing in DLP solutions is becoming a benchmark requirement.

Organisations implement DLP to safeguard various types of sensitive information, including:

Personally Identifiable Information (PII)

DLP helps protect customer and employee PII, such as:

• Social Security numbers
• Credit card details
• Email addresses
• Phone numbers

This ensures compliance with regulations like GDPR and CCPA.

Intellectual Property (IP)

Businesses use DLP to secure valuable IP, including:

• Trade secrets
• Product designs
• Source code
• Proprietary algorithms

DLP prevents unauthorised access and exfiltration of these critical assets.

Protected Health Information (PHI)

Healthcare organisations rely on DLP to safeguard PHI and maintain HIPAA compliance by protecting:

• Patient records
• Medical histories
• Lab results
• Billing information

Financial Data

DLP helps financial institutions secure:

• Account numbers
• Transaction records
• Investment strategies
• Financial reports

This aids in regulatory compliance and protects sensitive financial information.

More often, organisations are challenged by the growing reality that threats come from within. Whether through malicious intent, human error, or compromised credentials, insider-related incidents have become the dominant cause of data breaches.

“Sensitive data being sent to unauthorised accounts is a significant risk that organisations can’t afford to overlook,” emphasises cybersecurity expert Angela Morris. “Whether due to negligence, insider threats, or malicious leavers, the potential consequences of a data breach are too serious to ignore,” Morris says in an Insider Incident of the Month post.

Modern data loss prevention solutions operate through four core functions that work together to create comprehensive data protection across your organisation’s entire digital ecosystem.

Monitoring

DLP systems continuously scan data across three critical states: data at rest (stored files and databases), data in motion (email attachments, file transfers, web uploads), and data in use (documents being accessed or modified). Constant monitoring creates real-time visibility into how sensitive information moves through your environment. Beyond traditional networks, advanced monitoring now extends to cloud applications, mobile devices, and remote work scenarios.

Detecting

Detection engines combine contextual analysis with pattern recognition to identify sensitive information with remarkable precision. When your DLP solution encounters a 16-digit number in an email, regular expression matching helps determine whether it’s a credit card that needs protection or just a random sequence of digits.

Structured data gets special treatment through fingerprinting techniques that analyse database information for specific sensitive content. Meanwhile, file integrity relies on checksum analysis—essentially creating digital fingerprints using hashing algorithms to spot when important documents have been modified.

Organisations benefit from partial data matching when they need to find similar information scattered across different sources. Think of it as spotting the same form filled out by various employees but stored in different locations. For unstructured content like emails or documents, lexicon matching scans text using dictionary terms and custom rules to flag potentially sensitive information.

The most sophisticated detection comes from statistical analysis powered by machine learning. These advanced algorithms can spot patterns and anomalies that traditional rule-based systems miss entirely. Smart categorisation then determines whether detected data violates compliance requirements or company policies.

Blocking

When unauthorised data movement is detected, DLP systems respond with graduated enforcement actions tailored to your organisation’s risk tolerance. Response options range from complete blocking to data encryption or additional authentication requirements. Modern solutions also provide real-time coaching through policy tips that educate employees about risky behaviour without completely halting their productivity.

Blocking capabilities work across multiple channels—email, web browsers, USB devices, cloud applications, and mobile platforms. Smart enforcement considers user context, data sensitivity, and business requirements to avoid false positives that could disrupt legitimate work activities.

Reporting

Security teams gain powerful insights through comprehensive reporting that reveals data movement patterns, policy violations, and concerning user behaviours. Instead of drowning in alerts, real-time dashboards help you understand risk exposure and pinpoint areas needing stronger security controls.

The analytics go deeper than basic incident counts. You’ll discover which users trigger the most alerts, what types of data cause frequent violations, and which communication channels pose your biggest risks. For compliance teams, automated documentation simplifies regulatory audits by showing exactly how your organisation protects sensitive data and responds to policy violations.

Executive reports translate technical security metrics into business impact assessments, demonstrating ROI and guiding future security investments. This level of insight transforms data loss prevention from a reactive security tool into a strategic business enabler.

Here is how to initiate a successful DLP deployment:

• Prioritise data
  Every organisation has its own definition of critical data. The first step is to identify the most vulnerable forms of data that would result in the most significant damage if compromised. That’s where data loss prevention should start.
• Classify the data
  Classifying data by context offers an intuitive approach that can be scaled. Modern DLP programmes combine automated discovery tools with manual tagging to create comprehensive data maps that show where sensitive information lives and how it moves. That means classifying the source application, the data store, or the user who created the data.
  
  Applying consistent classification tags to the data allows organisations to track their use. Inspecting the content is also helpful in identifying regular expressions, such as Social Security and credit card numbers or keywords (for example, “confidential”). Content inspection often comes with pre-configured rules for PCI, PII, and other standards.
• Understand when data is at risk
  Distributing data to user devices or sharing it with third parties, customers, and the supply chain poses various risks. In these cases, the data is at the highest risk when used on endpoints. The rise of remote work and cloud adoption has expanded these risk scenarios significantly, with employees accessing sensitive data from personal devices and unsanctioned applications. Common scenarios involve sending sensitive data as an email attachment or transferring data to an external hard drive. A robust DLP programme must account for data mobility and when data is at risk.
• Monitor data in motion
  Understanding how data is used and identifying behaviour that puts data at risk is important. Advanced monitoring now leverages AI and machine learning to detect anomalous user behaviour patterns that may indicate insider threats or compromised accounts. Organisations must monitor data in motion to gain visibility into what’s happening to their sensitive data and determine the scope of the issues their DLP strategy should address.

Deploy in phases with simulation mode

• Begin all DLP policies in simulation mode to assess impact without disrupting business operations. This approach allows you to fine-tune detection rules, reduce false positives, and gather user feedback before full enforcement. Successful organisations typically progress through simulation mode, simulation with policy tips, and finally full enforcement over several weeks or months.
• Communicate and develop controls
  Engaging with business line managers is crucial to mitigating data risks and gaining insights into the underlying causes of data vulnerabilities. Data usage controls may be simple at the beginning of a DLP programme. Controls can target common behaviours that most line managers would agree are risky.
  
  As programmes mature, organisations develop more sophisticated, context-aware controls that consider user roles, data sensitivity, and business processes. Organisations can develop more granular, fine-tuned controls to reduce specific risks as the DLP programme matures.
• Train employees and provide continuous guidance
  Once an organisation understands when data is moved, user training can reduce the risk of insiders accidentally losing data. Employees often don’t recognise that their actions can result in data loss, and they do better when educated.
  
  Modern data loss prevention solutions provide real-time coaching through policy tips and user prompts that educate employees at the moment they encounter risky situations. Advanced DLP products offer “user prompting”, which notifies employees of data use that may be risky or against corporate policy. That’s in addition to controls that outright block risky data activity.

Integrate with broader security frameworks

• Connect your DLP programme with existing security tools like identity access management, zero trust architecture, and cloud access security brokers. This integration provides comprehensive protection and reduces security gaps that attackers might exploit. Regular audits and policy reviews ensure your DLP strategy adapts to evolving threats and changing business requirements.
• Rollout
  Some organisations repeat these steps with an expanded data set or extend data identification and classification to fine-tune data controls. By initially focusing on securing a subset of the most critical data, DLP is more straightforward to implement and manage. Successful pilot programmes also offer solutions to scale the programme. Over time, more sensitive information will be included, with minimal disruption to business processes.

Organisations face a variety of data threats that can compromise sensitive information. As cyber threats become more complex and damaging, understanding the primary risks is vital. Here are six key threats to be aware of:

• Phishing: You’ve likely encountered these deceptive emails or messages attempting to deceive you into revealing personal information. Phishing remains one of the most pervasive cybersecurity threats.
• Malware: This malicious software can infect your devices through various means. From viruses to worms, malware is designed to disrupt systems and steal data.
• Ransomware: Imagine your files suddenly locked, with a demand for payment to regain access. That’s the reality of ransomware, a growing concern for both individuals and businesses.
• Cyber-attacks: The plethora of cyber-attack strategies can take many forms, from denial-of-service attacks that crash your systems to sophisticated breaches that compromise entire networks.
• Insider risks: Sometimes, the threat comes from within an organisation. Whether it’s a disgruntled employee or someone who accidentally mishandles data, insider risks are a significant concern.
• Social engineering: This involves manipulating individuals into divulging confidential information. It’s not just about technology—it’s about exploiting human psychology.

Staying informed about these threats is the first line of defence. By understanding what you’re up against, you can take steps to protect your organisation from potential data breaches.

Misdirected email is one of the most prevalent forms of data loss caused by user carelessness. According to 2023 research, approximately one-third of employees sent one or two emails to the wrong recipient. For a business with 5,000 employees, this means an estimated 3,400 misdirected emails per year.

The consequences of sending an email to the wrong recipient can be severe:

• It’s one of the simplest forms of data loss, potentially exposing sensitive information to unauthorised parties.
• Even without sensitive data, it can cause embarrassment and reputational damage.
• Misdirected emails containing employee, customer, or patient data may trigger significant fines under regulations like GDPR.

Notably, 84% of misdirected emails contained attachments last year, further increasing the risk of data exposure. To mitigate this risk, organisations should implement advanced email security solutions that can detect and alert users to sensitive information in both email bodies and attachments. At Proofpoint, “Adaptive Email DLP uses behavioural AI and the industry’s broadest email datasets to analyse working relationships and understand the difference between safe business communication and sensitive data being sent to unauthorised accounts,” says Morris. “Adaptive Email DLP analyses more than six months of email data to learn employees’ normal email sending behaviours, trusted relationships, and how they handle sensitive data. Based on this learning, it accurately detects when unusual or unsafe email behaviour occurs.”

A DLP solution offers powerful benefits for organisations seeking to enhance their data security posture. Here’s how DLP transforms your data protection strategy:

• Meet regulatory requirements effortlessly: Whether you’re navigating HIPAA, PCI-DSS, GDPR, or other standards, DLP automates compliance monitoring and helps you avoid costly regulatory violations.
• Safeguard your competitive advantage: Your trade secrets, proprietary algorithms, and innovative designs stay protected from both external threats and insider risks.
• Gain complete data visibility: Discover where your sensitive information lives, how it moves, and who accesses it across your entire digital environment.
• Respond to threats instantly: Real-time alerts and automated responses help you contain threats before they become catastrophic breaches.
• Stop breaches before they happen: Advanced monitoring and intelligent blocking prevent unauthorised data movement, dramatically reducing your breach risk.
• Protect your bottom line: With the average data breach costing over $4 million, DLP provides measurable ROI by preventing devastating financial losses.
• Transform user behaviour: Immediate feedback coaching and policy tips turn risky user behaviours into security-conscious habits without disrupting productivity.

The result? Your organisation gains comprehensive protection that scales with your business, reduces risk exposure, and transforms data security from a reactive burden into a strategic competitive advantage.

Because attackers have numerous ways to steal data, the right DLP solution includes how data is disclosed. Here are the types of DLP solutions:

Email DLP

Defend against phishing attacks and social engineering techniques by detecting incoming and outgoing messages. Email DLP solutions can scan content, attachments, and links for sensitive information or malicious elements. They can also enforce policies to prevent the unauthorised sharing of confidential data through email channels.

Endpoint Management

For every device that stores data, an endpoint DLP solution monitors data when devices are connected to the network or offline. This type of DLP protects at the user level, monitoring activities such as file transfers, clipboard usage, and printing. Endpoint DLP can also enforce policies even when devices are disconnected from the corporate network, ensuring continuous protection.

Network DLP

Data in transit on the network should be monitored so that administrators are aware of any anomalies. Network DLP solutions inspect traffic flowing through the organisation’s network, identifying and preventing unauthorised data transfers. They can monitor various protocols and ports, providing comprehensive visibility into data movement across the network.

Cloud DLP

With more employees working from home, administrators leverage the cloud to provide services to remote staff. A cloud DLP solution monitors and protects data stored in the cloud. Cloud DLP extends data protection to cloud-based applications and storage, ensuring that sensitive information remains secure regardless of where it’s accessed or stored. These solutions can integrate with popular cloud services to provide consistent policy enforcement across multiple platforms.

Database DLP

Database DLP solutions focus on protecting sensitive information stored in structured databases. They monitor database activity, enforce access controls, and mask or encrypt sensitive data fields to prevent unauthorised exposure. These solutions also often provide audit trails and reporting capabilities to help meet regulatory compliance requirements and detect potential data breaches.

Data Discovery DLP

This DLP solution scans storage systems to identify and classify sensitive data across the organisation. Data discovery helps organisations understand where their sensitive information resides, enabling better data governance and protection strategies. By providing a comprehensive view of data assets, data discovery DLP solutions allow organisations to implement more targeted and effective data protection measures, reducing the risk of data loss or exposure.

Enterprise DLP

Enterprise DLP solutions provide comprehensive data protection across an organisation’s entire infrastructure. These solutions combine the functionalities of email, endpoint, network, cloud, database, and data discovery DLP into a unified platform. Enterprise DLP offers centralised policy management and enforcement, enabling organisations to consistently protect sensitive data across all channels and environments.

Human-Centric DLP

Human-centric DLP is a strategic evolution in data protection. Unlike traditional systems focusing solely on data classification and perimeter controls, this approach integrates behavioural analytics, user education, and adaptive policies to align security with workforce workflows. Gartner predicts that 50% of CISOs will adopt human-centric security strategies by 2027, driven by hybrid work models and sophisticated social engineering tactics.

“Every data breach study says the same thing – between 85% and 95% of all attacks are human-centred,” said Mike Stacy, Proofpoint’s Senior Director of Enterprise Security Strategy. “There’s no question about it.”

These solutions employ user and entity behaviour analytics (UEBA) to establish baseline activity patterns, detecting anomalies like sudden bulk file downloads or atypical cloud storage access. Proofpoint’s platform exemplifies this methodology by categorising user risk into three profiles: negligent employees mishandling data accidentally, compromised accounts exploited by attackers, and malicious insiders intentionally exfiltrating information.

DLP and Data Security Posture Management (DSPM) share the same goal of protecting sensitive information, though they approach data security from different angles. Understanding their distinct roles helps organisations build comprehensive protection strategies.

DLP focuses on data movement and transfer prevention. It acts as a digital gatekeeper, monitoring and controlling data as it flows through email, cloud uploads, USB transfers, and other channels. When an employee tries to send confidential information outside the organisation, DLP steps in to block or encrypt that action. This makes DLP excellent for preventing data from leaving your environment without authorisation.

DSPM takes a broader, more strategic approach to data security. Instead of focusing on data movement, DSPM looks at your entire data landscape. It discovers where sensitive information lives, assesses how well it’s protected, identifies access vulnerabilities, and continuously monitors your overall data security posture. Think of DSPM as creating a detailed map of your data risks before they become problems.

The key difference lies in timing and scope. DLP operates reactively at the moment of data transfer, while DSPM solutions work proactively to understand and secure data at rest within your infrastructure. DLP asks, “Is this data movement authorised?” while DSPM asks, “Do we know where all our sensitive data is, and is it properly secured?”

Together, they create powerful synergy. DSMP identifies what needs protection and where vulnerabilities exist, while DLP enforces protection policies when that data moves. This combination transforms data security from reactive blocking into proactive risk management.

When adopting and deploying a data loss prevention solution, it’s crucial to approach the process strategically to maximise effectiveness and minimise disruption.

• Define requirements: Clearly outline both business and security requirements. This includes compliance standards, data protection needs, and organisational goals. Understanding these requirements will guide your deployment strategy and ensure the DLP solution aligns with your organisation’s needs.
• Audit and classify data: Conduct a thorough audit of your infrastructure to identify where sensitive data is stored and how it’s transferred. Classify your data based on sensitivity and importance to prioritise protection efforts.
• Establish roles and responsibilities: Involve all relevant IT staff in the deployment process. Clearly define who is accountable for various aspects of the DLP solution, from policy creation to implementation and ongoing management.
• Document the process: Ensure your organisation has comprehensive documentation covering deployment procedures, operational guidelines, and training materials. This documentation serves as a reference for team members and supports compliance audits.
• Implement in phases: Start with a pilot test and gradually expand your DLP implementation. This phased approach allows your organisation to adapt to the solution and refine processes as needed.
• Regular review and training: Establish a plan for ongoing review and updates to your DLP policies and procedures. Conduct regular testing of DLP controls and provide continuous staff training to keep them informed about the latest threats and best practices.

With the right approach, organisations can effectively adopt and deploy a DLP solution that protects sensitive data, maintains compliance, and adapts to evolving security challenges.

Human-centric security is a paradigm shift in data loss prevention, recognising that employees can become your strongest line of defence when properly engaged. This approach integrates human behaviour to create more effective security systems.

How people interact with information fundamentally influences data security. By analysing behavioural patterns during file manipulation and application usage, organisations gain vital insights into potential risks before data loss occurs. Forrester confirms this approach, reporting that 68% of all data breaches are human error breaches.

Proofpoint is a pioneer in human-focused DLP. “Our DLP Transform and Insider Threat products have had tremendous adoption by customers; a majority of Fortune 100 customers are now using our information protection solution, and our endpoint DLP protection has grown over 75% year-over-year,” reports CEO Sumit Dhawan. “All of this is due to our human-centric approach that takes into account users’ activity and intent while protecting the information from leaking across all channels that users may be using,” he adds.

Rather than treating employees as security liabilities, human-centric DLP empowers them through contextual awareness and adaptive policies. This balanced approach reduces friction while maintaining robust protection across increasingly complex digital environments. By focusing on behaviour and motivation, organisations transform potential security weaknesses into strategic assets in their data protection strategy.

Proofpoint Data Loss Prevention offers integrated data protection for email and attachments. It stops accidental data exposure and prevents third-party attackers or impostor attacks via email. DLP can be leveraged with other information protection suite products, such as Proofpoint Data Discover and Proofpoint Email Encryption.

Our full-suite DLP tool is comprised of a central management server, network monitoring, storage DLP, and endpoint DLP. In small deployments, all components other than the endpoint agent may be consolidated on one server. Larger deployments may include multiple distributed pieces to cover different infrastructure elements.

With this tool, organisations always know where their private or proprietary data resides, including intellectual property, personal identification, financial information, and more. It helps organisations simplify discovery and quickly evaluate data to respond to any issue. The Proofpoint in-place DLP solution, Content Control, helps organisations:

• Easily locate sensitive data wherever it resides in the enterprise. The simplified discovery process notifies IS and IT teams of issues without requiring a complex DLP solution or a lock-it-all-down approach.
• Evaluate historical data and ensure that newly created data is evaluated. Quarantine or remove violations to prevent adverse effects caused by the wrong material. For example, if corporate content is discovered in a Dropbox synchronisation folder, the user is alerted, and the data is moved to the IT security team’s sanctioned repository.
• Evaluate the metadata and the full text within a file. This enables IT security departments to identify credit cards, personal identification, license numbers, etc. This process also teaches users best practices for data management and security on the job—without hindering productivity or workflow.

Proofpoint’s comprehensive DLP solutions extend data protection across email, cloud applications, and endpoints. These solutions provide deep visibility into user behaviour and data interactions, enabling effective detection and preventing data loss. With its unified console, cloud-native architecture, and advanced analytics, Proofpoint streamlines incident management and empowers organisations to efficiently safeguard sensitive data. To learn more, contact Proofpoint.