You don’t need a hacker to leak your data. Sometimes, all it takes is a poorly configured device, a careless human, or a misdirected email.
Also, if you thought that a data leak happens only because of a cyberattack, then that’s not the case. More often, it stems from simple oversights: an employee uploading files to a personal drive, a public cloud folder left unsecured, or confidential data shared over an unprotected channel.
In fact, IBM notes, the most common reason for data leakage is either human error or inadequately secured cloud storage and misconfigured firewalls[1].
What is data leakage and how can it be prevented?
So, if you are an IT admin who wants to learn more about data leakages or a CIO building data security strategies or simply someone who is interested in reading about data security. You are at the right place.
In this blog, we’ll understand the concept of data leakage and its causes, consequences, and discover the tips to prevent it.
Let’s start with the basics,
What is data leakage?
A data leakage occurs when any type of sensitive information is unintentionally exposed, either electronically or physically, to external unauthorized parties. Here’s how each of the two types of data leakage happens:
- Physical data leakage happens via misplaced printouts, lost or stolen USB drives, unsecured external hard disks, or discarded hardware containing sensitive data.
- Whereas, electronic data leakage may occur due to misconfigured cloud storage, insecure file-sharing apps, email misdeliveries, or unauthorized data transfers over the internet.
Now, you might think, “Aren’t data leakage, data breach, and data loss the same?”. They do sound similar, but no, they are not the same and have different meanings and reasons for taking place.
Data leakage vs Data breach vs Data loss: What is the difference?
So, these terms often get used interchangeably, but they describe different stages of risk. Let’s understand them in detail, which will help you respond to such situations more effectively.
Data leak
A data leak is accidental. It happens due to internal misconfigurations, weak access controls, or poor security hygiene. Think: someone uploads customer data to a public cloud folder without realizing it.
While data leaks are less intense in terms of immediate damage, they’re easier to prevent with the right policies, configurations, and user awareness.
Data breach
A data breach is usually deliberate and much more serious. It involves a targeted cyberattack by external actors who exploit vulnerabilities to gain unauthorized access. Breaches often follow a leak, because exposed data or weak configurations make it easier for attackers to get in.
Breaches tend to be high-impact events, often requiring incident response, regulatory disclosure, and brand damage control. Compared to data leakage, breaches are harder to detect and defend against, especially in real time.
Data loss
Data loss refers to the irreversible destruction or deletion of sensitive information, whether through human error, system failure, or malicious activity like ransomware. It is the most severe of the three. Once data is lost, recovery is either impossible or extremely costly.
Data loss has the highest business impact, especially if backups are outdated or missing. It’s also the hardest to recover from, making proactive protection absolutely essential.
To put it in one simple sentence, ‘Data leakage leads to data breach, which results in complete data loss.’
Types of information exposed in a data leak
Not all data leaks happen the same way. The type of information exposed often depends on how the data is being stored, accessed, or transmitted at the time of the leak. In cybersecurity, data is generally classified into three states: at rest, in transit, and in use. The risk is that leaks can occur at any of these stages.
1. Data at rest
This refers to information stored on a hard drive, server, database, or cloud storage. In simple terms, data that’s not actively moving.
Types of data commonly leaked in this state:
a. Personally Identifiable Information (PII)
b. Medical information (e.g., patient health records)
c. Trade secrets and intellectual property
d. Customer data
e. Company, federal, or business information
Leaks in this category often happen due to misconfigured storage buckets, weak access controls, or stolen physical devices.
2. Data in transit
This is data moving from one location to another, whether over the internet, through an internal network, or between apps and APIs.
Sensitive information vulnerable during transit includes
a. Account credentials (e.g., usernames, passwords)
b. Financial data (e.g., credit card numbers, bank details)
c. Company or business communications
If encryption protocols aren’t in place, data in transit can be intercepted via man-in-the-middle (MitM) attacks, unsecured Wi-Fi, or poorly secured email servers.
3. Data in use
Data in use is actively being accessed, processed, or modified—on a user’s screen, in a software tool, or inside an application.
Types of exposed information here may include:
- Account credentials
- Trade secrets and intellectual property
- Internal company data
- PII or customer data displayed in real-time systems
Leaks can happen through screen scraping, shoulder surfing, clipboard hijacking, or session hijacks. This happens often due to lack of endpoint security or weak user practices.
Thus, understanding how sensitive data behaves in each state will help organizations apply the right controls, such as encryption for data in transit, access restrictions for at-rest data, and strict endpoint policies for data in use, to minimize leakage risk across the company.
How does a data leak happen? 9 Common causes
Data leakage results from a combination of systemic gaps, process failures, and behavioral risks. While some causes are technical, others stem from a lack of oversight or user awareness. Here’s a breakdown of the most frequent and high-risk contributors:
1. Misconfiguration issues
Misconfigured cloud services, databases, firewalls, or access control lists (ACLs) are one of the most prevalent causes of data leaks. For example, leaving an Amazon S3 bucket publicly accessible or failing to restrict outbound traffic in firewall rules can expose critical data to the internet. These vulnerabilities often go undetected due to inadequate audits or automation errors in provisioning infrastructure.
2. Social engineering attacks
Attackers often bypass technical safeguards by targeting users directly. Social engineering methods—such as phishing, vishing, or credential harvesting via fake login portals—trick employees into divulging sensitive data or access credentials. Once compromised, attackers can move laterally through systems and extract large volumes of data undetected.
3. Human error
Accidental data exposure is a persistent challenge in both SMBs and enterprises. Examples include misaddressed emails containing confidential attachments, unsecured exports of sensitive reports, or failure to classify documents before sharing. These incidents often bypass traditional detection tools unless DLP (Data Loss Prevention) or content inspection systems are in place.
4. Weak or reused passwords
Credential hygiene remains a foundational issue. Users reusing passwords across multiple systems—or selecting simple, easily guessable passwords—make it easy for attackers to exploit brute force or credential stuffing attacks. This is especially risky in environments lacking multi-factor authentication (MFA) or centralized identity governance.
5. Lack of encryption policies
When organizations do not enforce encryption for data at rest and in transit, exposed data can be read and misused without resistance. Unencrypted databases, plain-text file transfers (e.g., via FTP), and unsecured APIs pose a serious risk, especially in industries where compliance with standards like GDPR, HIPAA, or PCI-DSS is mandatory.
6. Software or third-party vulnerabilities
Outdated software components, unpatched systems, and insecure third-party SDKs or APIs often contain exploitable flaws. Attackers may use these to execute remote code, elevate privileges, or exfiltrate data. Supply chain attacks are an advanced variant where compromised vendors indirectly leak customer or partner data.
7. Shadow IT
Unauthorized use of applications, cloud storage platforms, or communication tools by employees—often without IT approval—creates blind spots in an organization’s security posture. Because these tools aren’t monitored or protected by corporate policies, any data stored or transmitted through them is more likely to be leaked or mismanaged.
8. Insider threats
Data leaks can originate from employees, contractors, or partners who have legitimate access to sensitive data. These leaks may be intentional (e.g., data theft before resignation) or unintentional (e.g., copying confidential files to personal drives). Without user activity monitoring or role-based access control, such incidents are difficult to detect early.
9. Legacy systems
Outdated platforms and hardware that lack vendor support, security patching, or encryption support are easy targets for attackers. These systems often run on outdated protocols or OS versions, and their compatibility limitations make them resistant to modern security tools, thereby increasing the attack surface.
Notable recent data leakage incidents (2024–2025)
1. Phishing via Google Apps Script (May 2025)
Security researchers at Cofense, a phishing defense center, spotted threat actors abusing Google Apps Script development platform to host phishing pages that appear legitimate and steal login credentials.[2]
2. LexisNexis Risk Solutions (May 2025)
A breach exposed personal data, including Social Security numbers and driver’s license details, of over 364,000 individuals. The unauthorized access occurred via the company’s GitHub account.[3]
3. SEC’s Consolidated Audit Trail (April 2025)
An audit revealed elevated risks of data leakage due to insufficient safeguards in the SEC’s market surveillance tool, prompting security enhancements.[4]
4. National Public Data (August 2024)
A massive data leak compromised 2.9 billion records containing sensitive information like Social Security numbers and addresses. The breach led to the company’s bankruptcy.[5]
Why is sensitive data leakage a serious issue? Risks and consequences
Data leakage doesn’t happen in isolation. One leak can set off a chain of problems for an entire business. Let’s understand the consequences step by step, in the order they typically occur.
1. Identity theft: The first and most direct impact
When sensitive personal data like Social Security numbers, home addresses, dates of birth, or bank details is leaked, individuals are at immediate risk of identity theft.
This type of information can be used to impersonate someone online or offline. For example, cybercriminals can open unauthorized bank accounts, apply for loans, or file fraudulent tax returns using someone else’s name.
For instance, in late December 2024, the data leak at PowerSchool resulted in a data breach. This affected numerous U.S. school districts. It exposed sensitive information, including students’ and parents’ names, birthdates, home addresses, and Social Security numbers[6].
Thus, when customer data is leaked and identity theft follows, the blame often falls back on the organization responsible for securing the data.
2. Operational disruptions: Business as usual is no longer possible
Once a data leak is discovered, companies often have to act fast: disconnect affected systems, restrict access, or shut down certain operations to contain the problem. This disrupts normal workflows, delays projects, and affects service delivery.
In June 2024, a staff member at a UK-based mid-sized pathology service provider accidentally uploaded sensitive records to a public cloud folder. This data leak gave Qilin a Russian-speaking cybercriminal group the chance to exfiltrate and subsequently publish approximately 400GB of sensitive patient data, including names, NHS numbers, and blood test descriptions.
This breach postponed over 1,100 elective surgeries and more than 2,100 outpatient appointments at major London hospitals, including King’s College Hospital and Guy’s and St Thomas’ NHS Foundation Trust[7].
3. Compliance violations: Legal trouble follows quickly
When personal data is leaked, it often means that data protection laws have been violated. Different regions and industries have strict rules around handling sensitive data. Some of the major regulations include:
- GDPR (EU) protects the privacy of EU citizens
- HIPAA (U.S.) governs medical data
- COPPA (U.S.) and CIPA cover children’s online privacy and safety
- PCI-DSS focuses on payment card data security
Violating these regulations, even due to accidental leaks, can result in investigations, audits, and penalties.
Just like in January 2025, Solare Medical Supplies, a U.S.-based provider of home-delivered medical devices, faced a significant HIPAA enforcement action. The company was fined $3 million after a phishing attack compromised eight employee email accounts.
These accounts contained extensive electronic protected health information (ePHI), including Social Security numbers, credit card details, bank account numbers, medical diagnoses, and medication information. The breach affected 114,007 individuals[8].
4. Reputational damage: Trust takes the biggest hit
When people hear that their personal data was leaked, their trust in the organization drops. Clients may start questioning whether the company takes security seriously. Even loyal customers may begin to look for alternatives.
Once trust is lost, it’s difficult and expensive to rebuild. Future deals may fall through, and long-term brand value can take a serious hit.
In 2024, Ticketmaster, a global ticketing services company, experienced a major data breach after attackers accessed customer records stored in a third-party Snowflake database. Although the breach occurred between 2nd April and 18th May, customers weren’t informed until July 8, nearly seven weeks after detection.
This delay triggered a strong backlash, with users expressing frustration over the poor communication and lack of transparency. Ticketmaster had disclosed the breach in a May 31st regulatory filing, but withheld critical details. This left many unsure of what data had been compromised or what steps were being taken[9].
5. Financial losses: The final blow
All the previous consequences come with a cost. Businesses have to pay for incident response, legal consultations, regulatory fines, and customer notification services. They also lose revenue due to lost clients or paused operations.
According to IBM’s 2024 Cost of a Data Breach Report, the global average cost of a data breach has risen to $4.88 million, marking a 10% increase from the previous year. This increase is due to factors such as business disruption, lost customers, and expenses related to post-breach responses, including regulatory fines and customer remediation efforts[10].
Data leak prevention: Tips and best practices
Preventing sensitive data from leaking starts with building strong internal controls and maintaining clear visibility over who accesses what information, when, and how. Here are ten practical strategies businesses should follow:
Data leak prevention: Tips and best practices
When preventing data leakage about building layered, proactive security across people, processes, and technology. Below are ten advanced, enterprise-relevant practices, listed in the logical sequence an IT or security team would typically implement them.
1. Establish a data leakage prevention (DLP) policy
A data leakage prevention policy is the foundation. It defines:
- What counts as sensitive data (e.g., PII, PHI, IP, financial data)
- How it should be classified (public, internal, confidential, restricted)
- Acceptable data usage, transfer, and storage methods
- Incident reporting procedures and accountability roles
Once the policy is created, invest in good data leakage prevention tools to implement the policy in your organization.
Why it matters: Without policy, enforcement lacks direction. A documented policy is also mandatory under ISO/IEC 27001 and frameworks like NIST 800-53.
2. Discover and classify critical data assets
Use automated discovery tools to scan endpoints, servers, cloud platforms, and databases for unstructured and structured data. Once discovered, apply classification labels using metadata tags (e.g., “Internal Only,” “Restricted,” “GDPR-Protected”) to define access and handling rules.
Why it matters: You can’t protect data you don’t know exists. Classification helps automate DLP rules, encryption, access control, and audit trails.
3. Implement robust Data Loss Prevention solutions at all endpoints
Deploy agent-based DLP on endpoints, network DLP to inspect traffic, and cloud-native DLP for services like Google Workspace, M365 etc.
Key capabilities to enable:
- Real-time scanning of emails, file uploads, and clipboard actions
- Policy-based blocking, quarantining, or redaction
- Detection of sensitive data patterns (e.g., credit card numbers, SSNs)
Why it matters: A comprehensive DLP setup provides visibility and control across every exit point, including email, USBs, browsers, and cloud syncs.
4. Encrypt data in transit and at rest
For data at rest:
- Use AES-256 encryption for disk-level and file-level protection
- Enable BitLocker (Windows) or FileVault (macOS) on all endpoints
For data in transit:
- Enforce TLS 1.2+ across all network communications
- Use Business VPNs like Veltar or Zero Trust Access solutions like Scalefusion OneIdP
Why it matters: Even if data leaks or devices are compromised, encryption ensures the data remains unreadable without keys.
5. Enforce strong passwords and multi-factor authentication
Implement multi-factor authentication for all user and admin accounts and require employees to use complex passwords and rotate them regularly
Why it matters: 80% of breaches involve compromised credentials. Adding MFA reduces the risk of account compromise, especially in phishing scenarios.
6. Use granular access controls and Zero Trust principles
Move beyond traditional RBAC:
- Combine with ABAC (attribute-based access control) to consider user location, device posture, and time
- Apply Just-In-Time (JIT) admin access and Just-Enough-Access (JEA) via privileged access management solutions
- Monitor changes through audit logs and reports. UEM solutions like Scalefusion UEM allow you to get detailed reports and real-time activity logs.
Why it matters: Attackers exploit lateral movement. Least privilege access limits how far they can go after initial entry.
7. Control external sharing and shadow IT
Configure cloud DLP rules to:
- Block unauthorized third-party app connections
- Limit file-sharing permissions (e.g., view-only, expiration, watermarking)
- Detect and alert when sensitive data is shared via unauthorized channels like personal emails and USBs.
- Block USB access to devices used for work purposes.
Why it matters: Most accidental data leaks happen through legitimate tools being misused—such as someone sharing a Google Drive folder publicly by mistake.
8. Continuously monitor user activity and anomalies
Use UEBA (User and Entity Behavior Analytics) to detect:
- Data downloads that deviate from a user’s normal pattern
- Login attempts from unusual geolocations or devices
- High-volume file transfers to personal email or USB
Why it matters: Early detection is key. Most confidential data leaks begin with subtle activity before large-scale exfiltration.
9. Conduct periodic audits and simulate insider threats
- Perform internal red-teaming or simulated phishing + data exfiltration tests
- Review access logs, DLP reports, and privileged activity quarterly
- Include third-party vendors in security assessments
Why it matters: Not all threats are external. Insider threats, both accidental and intentional, are harder to detect without ongoing assessments.
10. Invest in a Unified Endpoint Management software
Adopt a centralized UEM solution like Scalefusion
- Enforce security policies like full-disk encryption, app whitelisting, and USB blocking
- Monitor and wipe data on lost/stolen devices
- Apply conditional access to work resources based on conditions like IP address, time, and day.
- Enforce full VPN tunneling to direct traffic from the secured gateway
- Manage access for input and output devices
- Apply policies to multiple devices and users at once
- Create device or user groups to simplify policy enforcement
Why it matters: Fragmented endpoint management creates blind spots. A unified platform like Scalefusion centralizes visibility and response for IT and SecOps alike.
Seal the data leak with Scalefusion
Preventing data leakage is not just about deploying tools. You need centralized visibility, the ability to enforce policies on devices in bulk, and to ensure accountability at every endpoint. Scalefusion provides you with a unified platform that empowers IT teams to manage devices and users, enforce security policies, and control how data moves across users and environments.
From blocking risky file transfers to wiping data from compromised devices in seconds, Scalefusion helps you stay ahead of leaks before they become liabilities. Whether you’re managing in office or remote teams, BYOD users, or frontline devices, Scalefusion brings the power back to the center.
Because in a world where one leak can cost millions, centralized management is critical.
References:
1. https://www.ibm.com/think/topics/data-leakage
3. https://www.theverge.com/news/675702/lexisnexis-data-broker-breach-social-security-numbers
4. https://www.reuters.com/world/us/elevated-risk-data-leak-sec-surveillance-tool-watchdog-says
5. https://en.wikipedia.org/wiki/2024_National_Public_Data_breach
6. https://convergencenetworks.com/blog/powerschool-data-breach/
7. https://www.bbc.com/news/articles/c9ww90j9dj8o
8. https://www.compliancepoint.com/healthcare/hipaa-enforcements-adding-up-fast-in-2025/
9. https://thereviewhive.blog/ticketmaster-data-breach-millions-potentially-affected/
10. https://www.rivialsecurity.com/blog/data-breach-cost-a-guide-for-financial-institutions-in-2025
