[Blog](/blog) Show links Resources [Blog](/blog) [Breaches](/breaches) [eBooks, reports, & more](/resources) [Events](/events) [News](/news) [Attack Surface Management](/category/attack-surface-management) Show links Categories [Attack Surface Management](/category/attack-surface-management) [Company News](/category/company-news) [Compliance and Regulations](/category/compliance-and-regulations) [Cybersecurity](/category/cybersecurity) [Data Breaches](/category/data-breaches) [DevOps](/category/devops) [Human Cyber Risk](/category/human-cyber-risk) [Risks and Vulnerabilities](/category/risks-and-vulnerabilities) [Third-Party Risk Management](/category/third-party-risk-management) [Vendor Risk Management](/category/vendor-risk-management) [How to Prevent Data Leaks](/blog/data-leak-prevention-tips) Publish date October 21, 2026 {x} minute read # How to Prevent Data Leaks [Get a demo](/contact-sales) [Free trial](/demo) [Scan my domain](https://www.upguard.com/tools/dark-web-scan) [Download the PDF guide](/resources/the-lean-security-teams-playbook-for-dark-web-incident-response) [Free trial](/demo) [Scan my domain](https://www.upguard.com/tools/dark-web-scan) Written by [Edward Kost](/team/edward-kost) Senior Cybersecurity Writer Edward is a cyber writer with a mechanical engineering background. His work has been referenced by academic institutions and government bodies. Reviewed by [Kaushik Sen](/team/kaushik-sen) Chief Marketing Officer Kaushik has a background in software engineering, enterprise solution architecture, and data analytics. He brings a unique, data-driven perspective to cybersecurity education. Table of contents Whitepaper The Lean Security Team's Playbook for Dark Web incident Response Free resource ### The Lean Security Team's Playbook for Dark Web incident Response [Download now](/resources/the-lean-security-teams-playbook-for-dark-web-incident-response) ‍[Data leak prevention](https://www.upguard.com/blog/how-to-detect-and-prevent-data-leakage) is a [cybersecurity](https://www.upguard.com/blog/cyber-security) practice that involves implementing secure data practices to reduce accidental exposure. Effective data leak prevention plays a crucial role in a comprehensive [data loss prevention strategy (DLP strategy](https://www.upguard.com/blog/data-loss-prevention)). [Data leaks](https://www.upguard.com/glossary/data-leak) are an easy [attack vector](https://www.upguard.com/blog/attack-vector) for cybercriminals. Exposed data, such as leaked credentials, allows unauthorized access to an organization's systems. This direct access enables hackers to carry out a range of [cyber attacks](https://www.upguard.com/blog/cyber-attack) with less effort, such as: * [Ransomware](https://www.upguard.com/blog/ransomware) and other types of [malware injections](https://www.upguard.com/blog/malware) * [Social engineering](https://www.upguard.com/blog/social-engineering), including [phishing](https://www.upguard.com/blog/phishing) * [Data exfiltration](https://www.upguard.com/blog/how-to-detect-data-exfiltration)/[data theft](https://www.upguard.com/blog/data-theft) ## What is a data leak? A [data leak](https://www.upguard.com/blog/data-leak) is an overlooked exposure of [sensitive data](https://www.upguard.com/blog/sensitive-data), either electronically or physically. Data leaks could occur internally or via physical devices such as external hard drives or laptops. If a cybercriminal locates a data leak, they can use the information to arm themselves for a [data breach](https://www.upguard.com/blog/data-breach) attack. When sensitive data is stolen from either a data breach[ or a ransomware attack](https://www.upguard.com/blog/protecting-employee-credentials-from-ransomware-compromise) and published on the dark web, these events are also classified as data leaks. ## The difference between data leaks and data breaches A [data leak](https://www.upguard.com/blog/data-leak) is the accidental exposure of sensitive information. These events are not initiated by an external impetus. They're caused by vulnerabilities in the security controls protecting confidential data. Data leaks can also be caused by cybercriminals publishing stolen data on their official dark web noticeboards, also known as ransomware blogs. A [data breach](https://www.upguard.com/blog/data-breach), on the other hand, is the outcome of a planned cyberattack. These events are initiated by an external impetus. Before sensitive data can be detected and exfiltrated, cybercriminals must overcome a series of data security measures securing the[ cyber kill chain.](https://www.upguard.com/blog/cyber-kill-chain) [Learn how to prevent data breaches >](https://www.upguard.com/blog/prevent-data-breaches) Data loss is another term commonly associated with data leaks. Data loss is the irreversible loss of sensitive data, either by accidental deletion or theft. These events can be mitigated with [Data Loss Prevention (DLP)](https://www.upguard.com/blog/data-loss-prevention) strategies that prevent data transfer beyond specified boundaries. However, a DLP strategy alone [will not prevent data leaks](https://www.upguard.com/blog/data-leak-prevention-tips); its focus is too narrow. [Data leak](https://www.upguard.com/blog/data-breach-vs-data-leak) prevention efforts need to consider all of the processes that have a direct and indirect impact on [sensitive data protection](https://www.upguard.com/blog/protecting-sensitive-data). This effort even stretches as far back as the [coding practices that develop a solution](https://owasp.org/www-pdf-archive/OWASP_SCP_Quick_Reference_Guide_v1.pdf). [Learn more about the differences between data leaks, data breaches, and data loss >](https://www.upguard.com/blog/data-loss-vs-data-leaks) ## What is data leakage protection? While related to DLP, data leakage protection refers specifically to the measures and technologies used to detect, monitor, and prevent sensitive data from being exposed or transferred outside an organization. This approach is proactive and highly focused, aiming to address the vulnerabilities and accidental exposures that often precede a major data breach. Data leaks are a common and easy attack vector for cybercriminals. Exposed data, such as leaked credentials, allows unauthorized access to an organization's systems. For instance, a proactive data leakage protection tool like UpGuard doesn't wait for a system to be breached; it searches the external environment for existing leaks. UpGuard can help prevent an attack by: * **Alerting on exposed credentials** found on the dark web, hacker forums, and ransomware blogs, allowing you to invalidate them before they are used to access your systems. * **Identifying leaked vendor information** that could be used in a supply chain attack gives you visibility into third-party risks that directly impact your security posture. A data leak is an overlooked exposure of sensitive data, whether it occurs electronically or physically. These events are not initiated by an external impetus; they're caused by vulnerabilities in the security controls protecting confidential data. A data breach, on the other hand, is the outcome of a planned cyber attack. ## **Essential data leak prevention tools** A successful data leakage protection strategy requires the right combination of tools that provide both internal monitoring and external visibility. These technologies help you detect and close security gaps before they can be exploited by an attacker. Here are the core technologies that enable an effective data leak prevention strategy: * **Data Loss Prevention (DLP) software:** These internal tools monitor and control data in transit and at rest within your network, typically by classifying sensitive information and enforcing policies to prevent unauthorized movement. * **Encryption and secure file transfer protocols:** Robust **encryption** should be used to protect data when it must be stored or transferred outside of specified boundaries, even if a leak occurs. * **Cloud security monitoring:** These tools continuously check for critical misconfigurations and vulnerabilities in cloud environments, such as exposed S3 buckets, which are a common cause of data leaks. * **Dark web scanning tools:** These are crucial for actively searching external sources, such as hacker forums and ransomware blogs, for leaked or stolen internal and third-party data that cybercriminals intend to exploit. * **UpGuard’s risk assessment and alerting tools:** These tools identify and continuously monitor your **external attack surface**, as well as that of your vendors’ networks, to detect security exposures before attackers do. ‍ ## Why is data leakage prevention important? Leaked data is a treasured find for a cybercriminal. These events significantly reduce the effort of cybercrime by removing all of the laborious stages preceding data compromised in the [cyber kill chain](https://www.upguard.com/blog/cyber-kill-chain). Because they make life so much easier for cybercriminals, data leak finds are becoming a primary focus in the world of cybercrime. Meeting this [performance metric](https://www.upguard.com/blog/cybersecurity-metrics) is relatively easy, given the growing prevalence of data leaks. [A 2021 UpGuard study revealed](https://www.upguard.com/resources/research-report-public-documents-used-for-attack-reconnaissance) that half of analyzed Fortune 500 companies were leaking data useful for cybercriminal reconnaissance in their public documents. Also, in 2021, [UpGuard researchers discovered](https://www.upguard.com/breaches/power-apps) that at least 47 organizations were unknowingly leaking data through a misconfiguration in Microsoft's PowerApp solutions - an oversight resulting in the exposure of tens of millions of private records. Many organizations unknowingly leak sensitive data sets, potentially exposing trade secrets, [Personal Identifiable Information (PII),](https://www.upguard.com/blog/personally-identifiable-information-pii) and even credit card data. The normalization of data breach prevention efforts will likely positively impact all other [cybersecurity sectors](https://www.upguard.com/blog/cyber-security). The degree of sensitive data exposure is proportional to the success of data breaches and [phishing attacks](https://www.upguard.com/blog/phishing). Both events could, therefore, be reduced if data leaks are remediated before cybercriminals discover them. ## What is data leakage protection? Data leak prevention is a cybersecurity practice that involves implementing secure data practices to reduce accidental exposure. Effective data leak prevention plays a crucial role in a comprehensive DLP strategy. While related to DLP, data leakage protection refers specifically to the measures and technologies used to detect, monitor, and prevent sensitive data from being exposed or transferred outside an organization. This approach is proactive and highly focused, aiming to address the vulnerabilities and accidental exposures that often precede a major data breach. Data leaks are a common and easy attack vector for cybercriminals. Exposed data, such as leaked credentials, allows unauthorized access to an organization's systems. For instance, a proactive data leakage protection tool like UpGuard doesn't wait for a system to be breached; it searches the external environment for existing leaks. UpGuard can help prevent an attack by: * Alerting on exposed credentials found on the dark web, hacker forums, and ransomware blogs, allowing you to invalidate them before they are used to access your systems. * Identifying leaked vendor information that could be used in a supply chain attack gives you visibility into third-party risks that directly impact your security posture. A data leak is an overlooked exposure of sensitive data, whether it occurs electronically or physically. These events are not initiated by an external impetus; they're caused by vulnerabilities in the security controls protecting confidential data. A data breach, on the other hand, is the outcome of a planned cyber attack. ## What causes data leaks? Data leaks occur when sensitive data is accidentally exposed publicly, either physically or digitally. Common causes of data leaks include: * [Misconfigured software settings](https://www.upguard.com/blog/cloud-misconfiguration) * [Social engineering](https://www.upguard.com/blog/social-engineering) * [Recycled or weak passwords](https://www.upguard.com/blog/the-password-security-checklist) * Physical theft/loss of sensitive devices * [Software vulnerabilities](https://www.upguard.com/blog/vulnerability) * [Insider threats](https://www.upguard.com/blog/insider-threat) [Learn more about the common causes of data leaks](https://www.upguard.com/blog/common-data-leak-causes) > ## Examples of data leaks The holy grail of sensitive information exposure is [Personally Identifiable Information](https://www.upguard.com/blog/personally-identifiable-information-pii) (PII), including names, contact information, financial details, and other personal data. Other less potent forms of data leaks can be used for [reconnaissance missions](https://www.upguard.com/news/terrorist-hackers-target-atlassian-oracle-servers) to uncover internal secrets. There are four major categories of data leaks - customer information, company information, trade secrets, and analytics. ### 1. Customer information Some of the [biggest data breaches](https://www.upguard.com/blog/biggest-data-breaches) included customer data leaks that involved Personal Identifiable information. Customer data is unique to each company. Customer confidential information could include any of the following: * Customer names * Addresses * Phone number * Email addresses * Usernames * Passwords * Social Security numbers * Payments histories * Product browsing habits * Credit Card numbers ### 2. Company information Leaked company information exposes sensitive internal activity. Such data leaks tend to be in the crosshairs of unscrupulous businesses pursuing the marketing plans of their competitors. Company data leaks could include the following: * Internal communications * Performance metrics * Marketing strategies ### 3. Trade secrets This is the most dangerous form of data leak to a business. Intellectual property theft destroys a business's growth potential, running it to the ground. Trade secret leakage could include the following types of data: * Upcoming product plans * Software coding * Proprietary technology information ### 4. Analytics Large data sets feed analytics dashboards, and cybercriminals are drawn to any sizable pool of data. Analytics software is, therefore, an [attack vector](https://www.upguard.com/blog/attack-vector) that needs to be monitored. Analytics data leaks could include the following: * Customer behavior data * Psychographic data * Modeled data ## Common hosts of data leak dumps There has been enough [data breach intelligence analyzed](https://www.upguard.com/blog/biggest-data-breaches) to paint a picture of common cybercriminal behavior. Thanks to this data, we can now deploy security controls along [each stage of the cyberattack lifecycle.](https://www.upguard.com/blog/what-is-an-advanced-persistent-threat) Data breach post-mortem analysis has also unveiled common cybercriminal behavior beyond a successful breach. After exploiting leaked data, the next stop for cybercriminals is usually dark web forums, where they either put it up for sale or publish it freely. Such forums need to be continuously monitored in a data leak detection strategy. Data leaks could still offer helpful reconnaissance information while in the process of being sold. Dark web marketplace listings often include a sample of compromised data to prove the authenticity of the event. By cross-referencing the sample information against your [third-party vendor](https://www.upguard.com/blog/third-party-vendor) list and a database of known breaches, such as [Have I Been Pwnd](https://haveibeenpwned.com/), the source of the leak could be identified. The following popular dark web forums should be monitored for data leaks: * Nulled * Dread * Crackingking * Cryptbb * Raidforums * Freehacks * Hacktown * Xss.is * exploit.in * evilzone.org * 4chan [Learn how to reduce data leak false positives >](https://www.upguard.com/blog/how-to-reduce-false-positives-in-data-leak-detection) ### Ransomware blog data leaks Another common cause of data leaks is data dumps from ransomware attacks. Hackers publish data stolen from ransomware attacks on dark websites known as ransomware blogs (or ransomware sites). Ransomware blogs are like noticeboards for specific ransomware groups, hosting official updates as well as data dumps. A data leak prevention strategy must accommodate for these types of leaks by implementing security measures beyond the final phase of the ransomware attack lifecycle - after the data dump phase (phase 8). [Learn how to reduce the impact of ransomware attacks >](https://www.upguard.com/blog/protecting-employee-credentials-from-ransomware-compromise) A ransomware data leak security tool monitors popular ransomware blogs for critical data and internal confidential information (like employee credentials leaks). If ransomware leaks are left unaddressed, cybercriminals could use them to instantly gain access to a private network without the usual social engineering processes that preclude unauthorized access attempts. Armed with internal credentials from a ransomware blog, cybercriminals could circumvent the perimeter penetration phases - the most difficult stages of a ransomware attack - leaving just the challenge of escalating permissions before a breach is achieved. The resulting compressed ransomware lifecycle, which makes data breaches easier and faster to accomplish, highlights the critical need for ransomware leak security measures in security policies. [Request a free demo of UpGuard's ransomware data leak solution >](https://www.upguard.com/demo) ## Addressing the source of data leaks The most effective and sustainable cybersecurity initiatives are those that assume a [proactive approach to protection](https://www.upguard.com/blog/prevent-supply-chain-attacks-with-zero-trust-architecture). Data leak monitoring efforts are reduced if the vulnerabilities facilitating data leaks are addressed. This is most efficiently achieved with [an attack surface monitoring solution](https://www.upguard.com/product/breach-risk). Such a solution will discover the security vulnerabilities inside your ecosystem and those throughout your third-party vendor network. Monitoring the third-party attack surface is crucial [since over half of data breach events](https://www.idagent.com/blog/supply-chain-cybersecurity-risk-is-swamping-businesses/#:~:text=Over%2090%25%20of%20US%20businesses,exposure%20through%20a%20third%20party.) result from compromised third-party vendors. Since most breaches stem from compromised third parties, it's safe to assume that your vendors aren't addressing data leaks in their cybersecurity practices. Because of this, the scope of a data leak detection strategy should also extend to the third-party landscape. Since data leaks commonly preceded data breaches, this effort will reduce third-party breaches and [supply chain attacks](https://www.upguard.com/blog/supply-chain-attack) and, therefore, most data breach events. ## 8 tips to protect your business from data leaks in 2025 The following [data security](https://www.upguard.com/blog/data-security) practices could prevent data leaks and [minimize the chances of data breaches](https://www.upguard.com/blog/prevent-data-breaches). ## **8 tips to protect your business from data leaks** The following [data security](https://www.upguard.com/blog/data-security) practices could prevent data leaks and [minimize the chances of data breaches](https://www.upguard.com/blog/prevent-data-breaches). ### **1. Perform regular risk assessments** Since over half of data breach events result from compromised third-party vendors, monitoring the third-party attack surface is crucial. * **Monitor vendor security posture:** Vendor risk assessments are a common method of identifying third-party security risks and ensuring compliance with regulatory standards, such as [HIPAA](https://www.upguard.com/blog/hipaa-privacy-rule),[ PCI-DSS](https://www.upguard.com/blog/compliance-monitoring#toc-payment-card-industry-data-security-standards-pci-dss-), or[ GDPR](https://www.upguard.com/blog/sensitive-data). * **Use security scoring for efficiency:** Security scoring is a highly efficient way of evaluating a vendor's susceptibility to data breaches. The UpGuard platform assigns all vendors a security score based on an analysis of 70+ critical vectors. ### ‍ [Learn more about UpGuard's security rating feature >](https://www.upguard.com/product/security-ratings) ### **2. Limit access control** Your confidential data may currently be accessible to users who don't require it. * **Enforce least privilege:** Evaluate all permissions to ensure access isn't being granted to unauthorized parties. * **Segment data:** Categorize all critical data into different levels of sensitivity to control access to different pools of data. This privileged access assignment process may also identify malicious insiders. ### **3. Identify and classify all sensitive data** Before DLP policies can be initiated, businesses need to identify all of the sensitive data that needs to be secured. * **Discovery and classification:** This data then needs to be correctly classified in line with strict security policies. Classification categories could include [Protected Health Information (PHI)](https://www.upguard.com/blog/protected-health-information-phi), financial data, and other sensitive data forms. * **Tailor defenses:** Correct classification allows a business to tailor the most efficient data leak prevention defenses for each data category. ### **4. Secure all endpoints and educate employees** With most organizations now adopting remote working models, endpoints have become more challenging to secure. * **Extend endpoint coverage:** Extend your coverage to cloud-based endpoint security, covering all remote access points, including [IoT](https://www.upguard.com/blog/internet-of-things-iot) devices, desktops, and mobile devices. * **Train against social engineering:** Staff are often tricked into introducing malware to bypass security defenses. Organizations need to train their staff to recognize the trickery of cyberattackers, particularly **email phishing** and [social engineering](https://www.upguard.com/blog/social-engineering) attacks. ### **5. Implement a layered DLP strategy** Data loss prevention (DLP) is an overarching data protection strategy that should include data leak prevention as a core component. An effective DLP system combines processes and technology. * **Apply internal controls:** DLP components include securing data in motion, securing endpoints, securing data at rest, and securing data in use (monitoring unauthorized user behavior). * **Add external leak detection:** If data leak prevention strategies fail, fast remediation is crucial to preventing a data breach. Effective [data leak detection](https://www.upguard.com/product/breach-risk/threat-monitoring) tools (like UpGuard’s threat monitoring) can scan the open and deep web for data exposures, including S3 buckets and GitHub repositories, enabling faster removal of potential breach vectors. ### **6. Encrypt all data** Cybercriminals may struggle to exploit data leaks if the data is encrypted. * **Use encryption as a layer:** [Encryption](https://www.upguard.com/blog/encryption) (Symmetric-Key or Public-Key) should not be the sole data leak prevention tactic, but rather used in conjunction with other methods. [Learn how tech companies can detect data leaks >](https://www.upguard.com/blog/how-tech-companies-can-detect-data-leaks) ### **7. Proactively monitor external sources** Data breach post-mortem analysis has unveiled common cybercriminal behavior: after exploiting leaked data, the next stop is usually dark web forums, where they either put it up for sale or publish it freely. * **Scan ransomware blogs:** Another common cause of data leaks is the publication of data dumps from ransomware attacks on dark websites known as ransomware blogs. * **Use threat monitoring:** A ransomware data leak security tool monitors popular ransomware blogs for critical data and internal confidential information. [UpGuard’s threat monitoring](https://www.upguard.com/product/breach-risk/threat-monitoring) helps organizations identify and strengthen security vulnerabilities to prevent reconnaissance campaigns. ### **8. Patch and address software vulnerabilities** The most effective and sustainable cybersecurity initiatives are those that assume a proactive approach to protection. * **Use attack surface monitoring:** Data leak monitoring efforts are reduced if the vulnerabilities facilitating data leaks are addressed. This is most efficiently achieved with an attack surface monitoring solution. * **Cover vendors:** Such a solution will discover the security vulnerabilities inside your ecosystem and those throughout your third-party vendor network. > The UpGuard platform assigns all vendors a security score based on an analysis of 70+ critical vectors. ## **Key takeaways** Preventing accidental data exposure is a multi-layered effort that focuses on both your internal environment and your external attack surface. To recap the most essential actions and strategies: * **Data leaks are preventable** with the right visibility and tools—the goal is to find the exposed data before cybercriminals do. * **DLP software and real-time external alerting** (such as dark web scanning) play a critical role in detecting and remediating exposures across all stages of the attack lifecycle. * **UpGuard supports proactive detection and third-party monitoring** to provide a comprehensive, external view of your attack surface and supply chain risk. * **Regular assessments and continuous monitoring** of both your own environment and your vendors' security postures are crucial to identifying and closing security gaps before they are exploited. ‍ ‍ Whitepaper The Lean Security Team's Playbook for Dark Web incident Response Free resource ### The Lean Security Team's Playbook for Dark Web incident Response [Download now](/resources/the-lean-security-teams-playbook-for-dark-web-incident-response) ## Related posts Learn more about the latest issues in cybersecurity. Attack Surface Management #### [Find Out if You're Exposed on the Dark Web](/blog/find-out-if-youre-exposed-on-the-dark-web) Answer 5 quick questions to predict what a dark web scan will find about your company. Then run the free scan to see your real exposure. [](/team/lance-turner) [Lance Turner](#) October 14, 2026 Data Breaches #### [Your First Dark Web Scan Report, Explained](/blog/your-first-dark-web-scan-report-explained) You scanned your domain. What do the results mean? [](/team/lance-turner) [Lance Turner](#) October 13, 2026 Data Breaches #### [Good Security Rating? Your Dark Web Exposure Says Otherwise](/blog/good-security-rating-your-dark-web-exposure-says-otherwise) Scan your domain to see just how exposed you are on the Dark Web. [](/team/lance-turner) [Lance Turner](#) October 13, 2026 Attack Surface Management #### [Shadow MCP Servers: The AI Infrastructure You Can't See](/blog/shadow-mcp-servers) In 2012, it was Dropbox. In 2026, it’s Shadow MCP. Discover why unvetted AI agents are an invisible threat and how to regain total visibility. [](/team/shane-moosa) [Shane Moosa](#) August 25, 2026 Attack Surface Management #### [Six MCP Security Incidents Every Security Leader Should Know](/blog/mcp-security-incidents) From registry poisoning to filesystem wipes: discover the 6 MCP security incidents every leader must know to secure their AI agent workflows in 2026. [](/team/shane-moosa) [Shane Moosa](#) July 1, 2026 Attack Surface Management #### [1 in 15 MCP Servers are Lookalikes: Is Your Org at Risk?](/blog/mcp-server-lookalikes) For every official MCP server, up to 15 lookalikes exist. Learn to identify these registry-layer threats and discover methods to protect your organization. [](/team/shane-moosa) [Shane Moosa](#) May 12, 2026 [All posts](/blog) Experience superior visibility and a simpler approach to cyber risk management [Get a demo](/contact-sales) [Free trial](/demo)