How trusted access creates hidden exposure—and how security, IT and business teams can reduce insider risk

Takeaways

• Insider threats aren’t just malicious. Negligence, honest mistakes and compromised accounts account for a significant share of insider-driven incidents.
• Risk increases during key lifecycle moments. Onboarding, role changes, high-pressure deadlines and employee exits consistently correlate with higher insider risk.
• Resilience matters more than trust. Effective insider risk management focuses on least privilege, monitoring for behavior patterns and designing security controls that fit real workflows.

Insider threats are among the most underestimated and unexpected risks that companies face. Incidents that originate from an identity with trusted access are almost always harder to detect and track than incidents that get through broken defenses. Research shows insider incidents cost organizations an average of $17.4 million per year, with compromised credentials and negligent user actions driving the highest financial impact and longest detection times. These incidents often take months to identify, mitigate and investigate. The 2025 Verizon Data Breach Investigations Report (DBIR) also reveals that insiders are involved in the majority of breaches, whether through error or malice. Insiders pose a legitimate risk to every size company in every sector.

Insider threats extend beyond malicious employees. Any user can unintentionally create risk to the company, so if you’re thinking about insider risk management, consider this definition from the experts at Carnegie Mellon University:

Insider Threat – the potential for an individual who has or had authorized access to an organization’s critical assets to use their access, either maliciously or unintentionally, to act in a way that could negatively affect the organization. ~Daniel L. Costa, CERT Insider Threat Center, Software Engineering Institute (SEI)

This definition is broad enough to include any type of risk from any type of insider threat. This will help you keep insider risks visible in your security strategy.    

The main types of insider threats

Malicious insiders causing intentional harm

Just like they sound, these are the ones who want to steal company secrets, destroy digital assets, leak sensitive data or otherwise harm the company.

There are several motives for these destructive activities. Disgruntled employees may want to punish the company or a fellow employee. Opportunists may accept payment from threat actors to provide access or competitors to provide information. This risk rises sharply around departures, so companies should maintain a disciplined offboarding or exit program.

Negligent insiders who unintentionally create risk

People with trusted access don’t always want to follow the rules. They might not intend to harm anyone, but they reuse passwords, click on spam out of curiosity, ignore sensitivity labels, and otherwise bypass security controls because it’s easier or faster than following protocol.

Most of the time, these people think they’re solving a problem. They need something fast so they email files to themselves so they can work after hours, or they share credentials because multiple people need access to a single-user resource. This may be reduced by examining how security processes fit with workflows. If a user is “just trying to get things done,” there may be a better way to secure the affected systems. Training may help them understand the “why” behind the controls. Gathering feedback from these users can help get their buy-in if the security policies are updated.

Insiders who make honest mistakes

Often referred to as “accidental insiders,” these users might misaddress email, misconfigure security policies or store sensitive data in an unprotected space. These users are not malicious or negligent, but they commit errors that lead to exposure.  

Every human will make a mistake, especially when rushed or fatigued, but there may be some environmental factors that can help reduce this risk. Regular security audits and automated scanning can identify security gaps and vulnerabilities that may be overlooked by IT teams. Clear data sensitivity rules and automated encryption can make security easier on the users.

Compromised insiders that unintentionally provide access to attackers

This describes an insider whose access has been ‘hijacked’ by an external threat actor. The threat actor gains control of a legitimate account and operates as the user, blending into normal traffic and working slowly to gain more access without triggering alerts. This frequently begins as phishing or accidental malware installations. You can see a classic example of this in the August 2025 attack on Nevada.

Third‑party insiders

Vendors, contractors and other third-party partners often have legitimate access to a domain but operate under a different set of controls and oversight. This expands your attack surface and can create blind spots in your security posture. While you may trust your third-party partners, you should keep in mind they also face insider risks and other threats.

You can mitigate this risk by enforcing segmentation, strong identity controls, least-privilege and just-in-time access, and other best practices.

Predicting insider risk

Insider risk isn’t evenly distributed throughout employment or a partnership. The risk level will increase based on events and other stressors.

Best practices to mitigate insider threats

• Build an insider risk management (IRM) program: Establish a formal program that treats insider risk as a cross-functional business risk, not just a security problem. Include security, IT, HR, legal, and compliance stakeholders.
• Apply least privilege with just-in-time (JIT) access: Grant elevated privileges only when needed and revoke them when done. This may require more administrative tasks than providing standing access, but it reduces the impact of malicious insiders, compromised accounts and third-party misuse.
• Design security controls around workflows: Users like to avoid friction, especially when it comes to security controls. Review how employees work and redesign processes so the secure path is the easiest possible path.
• Automate protection wherever possible: Automatic encryption and default-secure sharing settings will help eliminate human error.
• Strengthen identity and authentication: Enforce unique identities and multifactor authentication (MFA) for all users. Adopt and enforce zero trust principles like continuous authentication and session monitoring.
• Monitor for risk patterns: Focus detection on unusual combinations of actions, like data access followed by local download and external transfer.
• Adjust controls as needed: High risk windows like onboarding, vendor transitions, role changes and employee exits may require restricted access and heightened monitoring.
• Automate cloud, application and device configuration where possible: Automation lowers error rates and limits damage when mistakes occur. Automated scanning for vulnerabilities can help prioritize mitigation.
• Treat third-party access as a separate risk domain: Segment third-party access and enforce individual identities and other technical controls.

Managing insider risk isn’t about whether employees or partners can be trusted — it’s about resilience. Organizations should design systems to withstand insider mistakes, misuse or compromise when—not if—they occur.

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