Insider Threats: Definition, Types, and How to Tackle Them

In August 2020, Anthony Levandowski was sentenced to 18 months in prison. The former Google engineer and pioneer of self-driving car technology pleaded guilty to stealing trade secrets from the search giant’s self-driving car project, Waymo. 

Levandowski launched his own self-driving car startup, Otto, and sold it to Uber in 2016 for over $600 million. The following year, Waymo sued Uber for theft of trade secrets. According to the Justice Department, before Levandowski resigned from Google, he downloaded thousands of files related to their self-driving car program.  This story highlights the risk of insider threats. Many leaders understand the importance of defending against hackers and other external bad actors looking to break into a system, but there are also risks posed by internal actors that can be just as damaging.

This is just one example of a high-profile insider threat. Let’s take a look at what these threats are and how cyber threat intelligence plays a critical role in mitigating such risks.

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What Is an Insider Threat?

Insider threats are cybersecurity risks that come from within an organization, posed by authorized users who have legitimate access to an organization's assets or premises. These bad actors might be current or former employees, contractors, business partners, or anyone with authorized access to systems or data.

With fewer barriers to overcome to gain access to company secrets or intellectual property, bad actors could easily be tempted to make a move against their own company. While external attackers are largely motivated by financial gains, it seems insiders act upon a variety of other factors too, including taking revenge for a workplace grudge.

Not all insider threats are malicious. Well-intentioned staff, contractors, and partners can input sensitive data into third-party tools without knowing if those tools meet security standards.

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Why Is It Important to Identify Potential Insider Threats Early On?

Identifying potential insider threats is crucial because insiders can cause devastating damage with their legitimate access and inside knowledge, potentially leading to massive financial losses and operational collapse. Early identification creates opportunities to address underlying issues before harmful incidents occur, or at least before they cause serious damage, potentially saving both the employee and the organization from disaster.

Ultimately, organizations have legal and ethical obligations to protect sensitive data and failing to address insider risks can result in severe penalties, lawsuits, and permanent reputational damage that destroys customer trust.

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The Most Common Types of Insider Threats 

To properly defend against these sorts of attackers, you first need to know what to look out for. There are five main types of insider threats that your organization should be keeping an eye out for.

1. The Unintentional Insider

This is your human error factor. It breaks down into two types:

• The Negligent Insider: They know the rules but choose to bend them—skipping a security update, letting someone tailgate into a secure area, or using an unauthorized USB drive. It’s not malicious, but it's a critical vulnerability created by carelessness.
• The Accidental Insider: This is a pure mistake. Think of sending a sensitive file to the wrong email address or clicking on a phishing link without thinking. There's no ill intent, but the damage can be just as severe.

2. The Malicious Insider

This is the classic bad actor. Driven by greed, revenge, or ego, they intentionally steal data, sabotage systems, or leak intellectual property. They are actively working to harm the organization from the inside out.

3. The Collusive Insider 

This is a team effort, and a dangerous evolution of the malicious insider. Here, one of your own collaborates with an external attacker—like a cybercriminal ring or a competitor—to orchestrate a breach. They are the inside man for an outside job. 

4. The Third-Party Insider

The modern workforce is fluid, and so is the insider threat. This category includes contractors, vendors, and partners. They have legitimate access to your systems and people, but they aren't formally part of your organization, creating a unique and often overlooked risk vector.

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How to Prevent Insider Threats

To truly defend against insider threats, you need to make security everyone’s priority. Moving from rules on a page and tick-box training to a continuous, security-first culture will help keep your organization safe.

Here’s how to make that happen:

• Codify Your Expectations: Don't leave security to chance. Implement crystal-clear policies that define acceptable use for all your networks, systems, and data. The goal is not to restrict, it's to set a baseline for secure operation so everyone knows exactly what's expected of them.
  
  
• Manage the Full Employee Lifecycle: Your vigilance must extend from hire to retire. This means robust background checks and integrity assessments for anyone handling sensitive assets—not just once, but continuously. When people change roles or leave, have a concrete plan that includes exit interviews and ensures a clean, secure off-boarding process.
  
  
• Forge a Human Firewall with Continuous Training: One-and-done training is useless. Build a culture of security awareness with mandatory, engaging, and continuous training. Go beyond basic phishing simulations. Tailor the content to your specific environment and the real-world threats your team faces. Make security awareness a constant practice, not an annual event.
  
  
• Secure Your Supply Chain: Your security perimeter now includes your partners and vendors. Establish ironclad security agreements with any third party that touches your data. Prioritize transparency by monitoring and logging who accesses your information and when. Vet your partners, build long-term trust, and ensure there are clear legal and jurisdictional safeguards for your data, no matter where it resides.

 Kev Breen, Senior Director, Cyber Threat Research at Immersive, explains it best:

“You have new technology coming in and new people starting, so you can't rely on playbooks. True preparedness is being able to identify and respond to any threat.”

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Mitigate Cyber Threats with Immersive

When it comes to insider threats, your defense can't be a document you hand out during onboarding. A negligent click or a moment of carelessness is all it takes to bypass even the most advanced technical controls. The threat isn't static, so your training can't be either.

Traditional security awareness training is no longer enough. True defense against insider threats—both accidental and malicious—is built through continuous, relevant training that creates security muscle memory.

Don't wait for human error to become your next critical incident. The threat is already inside your walls. The only question is whether your team is continuously prepared to face it.

Want to learn more? Book a demo today.