What is a Data Leak? Causes, Examples, and How to Prevent Them

One careless click, one misconfigured server, or one overlooked vendor vulnerability — suddenly your company’s confidential data is exposed for everyone to see. This isn’t a hacker’s masterstroke; it’s a classic data leak. 

In this glossary post, we’ll explain what data leaks are and why they’re a growing concern you can’t afford to ignore. We’ll also shed light on common data leak scenarios with real-life examples, explain their root causes, and provide practical, actionable steps you can take to prevent data leaks in your organization.

Understanding data leaks

A data leak is essentially an unauthorized disclosure of confidential information to an external party. Data leaks can be either accidental or intentional and have serious consequences for the organizations affected.

Cybercriminals can use leaked financial information, health records, login credentials, intellectual property, or personal identifiable information (PII) to engage in fraud, identity theft, or blackmail. 

The consequences of data leaks may include:

• Financial losses — direct (e.g., incident response expenses) and indirect costs (e.g., lost business opportunities).
• Reputation damage — decrease in customer trust and brand value.
• Regulatory penalties — fines and lawsuits.
• Operational disruptions — interruptions to business continuity, productivity, or service delivery.
• Loss of competitive advantage — exposure of trade secrets or strategic plans that allows rivals to gain an edge.

Data leaks often stem from preventable mistakes or overlooked vulnerabilities. Understanding what typically causes data leaks is crucial for effectively mitigating the risks.

Common causes of data leaks

Below, we break down the most common examples of data leaks, from oversights to security vulnerabilities. 

Poor security policies

Without clear rules for handling data, employees may follow inconsistent practices that increase the risk of data leaks. Outdated or vague policies create gaps that lead to poor decisions, like sharing documents through unprotected channels or skipping encryption. For instance, without a specific policy on remote work data storage, an employee might store files on an unsecured personal device, inadvertently exposing sensitive information.

Weak passwords

Weak, reused, or default passwords remain a major security gap. Without enforced policies for strong, unique, and regularly updated passwords, attackers can easily crack credentials using brute-force or credential-stuffing techniques. Failing to implement multi-factor authentication (MFA) further compounds the risk, as it gives cybercriminals easy access to sensitive systems and data.

Network misconfigurations

Even a single mistake in configuring your IT infrastructure can expose massive amounts of data. In one real-world example of this, in 2023, a single misconfigured Azure Blob Storage SAS token at Microsoft left 38 TB of data exposed to the public. Skipping authentication and leaving storage publicly accessible can open the door for attackers or even random users to access sensitive data without any hacking at all.

Software vulnerabilities

Unpatched or outdated software can also cause data leaks. Attackers actively attempt to exploit known software vulnerabilities to gain access to targeted organizations. Beyond any threats posed by malicious outsiders, flawed software might also inadvertently expose data through logs, debug modes, or broken access controls. 

Third-party security flaws

Even if your own systems are secure, third parties can also cause leaks. If your vendor uses unpatched software or handles your data insecurely, they may accidentally leak your data. For example, the infamous Sisense data leak of 2024 allowed attackers to exploit hardcoded credentials found in a third-party vendor’s GitLab repository.

Human error

Employees’ mistakes remain one of the most frequent causes of data leaks. The element of human error may arise in seemingly simple scenarios, such as an employee sending an email to the wrong recipient or accidentally saving a report in a publicly accessible cloud storage folder. Phishing and social engineering can also exploit human lapses, tricking employees into inadvertently sharing data. 

Insider threats

Malicious insiders, such as disgruntled employees or contractors, can also leak sensitive data. Unlike external attackers, insiders already have some level of access to your systems, making it easier for them to bypass your security controls.

Use of AI

Generative AI tools like ChatGPT introduce a new kind of data exposure risk. When employees feed sensitive internal information into public AI chatbots, that data may be retained, processed, used to train future models, or even exposed to other users. 

By addressing these root causes, organizations can significantly reduce the risk of data leaks.

How to prevent data leaks 

It’s essential to adopt a comprehensive and layered security strategy that addresses all possible sources of data leaks.

Create and regularly update security policies

Establish clear information security policies, including data-handling rules, and distribute them among your employees. Enforce robust cybersecurity measures, such as encryption, multi-factor authentication, and data backups. Regularly review and revise your data protection policies to ensure they cover new emerging threats. 

Secure access to data

Follow the principle of least privilege and only grant employees and systems the minimum access needed. Continuously review permissions and promptly revoke access to sensitive data when a user or application no longer requires it.

Keep an eye out for software updates

Update your software as soon as vendors issue patches that fix vulnerabilities. Pay special attention to cloud applications or unauthorized software that employees may be using. Regularly audit your IT environment to identify shadow IT and provide secure, approved alternatives to your employees that meet their needs safely.

Conduct cybersecurity awareness training

Cybersecurity training and clear guidance on handling sensitive data can significantly contribute to preventing data leaks by cultivating awareness and careful behavior among employees. Regularly educate and train your team on security best practices. Employees should know how to spot phishing and how to handle data safely. 

Manage third-party security risks

Evaluate the security practices of your existing and potential vendors. Insist they comply with your security standards by implementing measures like contractual agreements, regular assessments, and audits to combat third-party vulnerabilities. It’s also essential to monitor third-party activity within your systems.

Implement dedicated tools

Use data loss prevention (DLP) solutions to automatically detect and stop sensitive data from leaving your environment. User activity monitoring (UAM) tools can further enhance visibility into how sensitive data is accessed and handled across your organization.

Syteca offers advanced user activity monitoring and privileged access management solutions to tightly control elevated accounts and catch risky user activity within your network. Combined with the best practices described above, Syteca can help you stay ahead of data leaks and protect your organization’s most critical information.