When you think of ransomware, data breaches, and other cyberattacks, what type of person comes to mind? A hooded hacker in a dark internet cafe? In reality, 95% of data breaches involve a company’s own employees. To build strong cybersecurity defenses, your organization must learn to recognize the indicators of insider threats.
The situation is urgent. According to a recent report, nearly 85% of enterprises experienced at least one insider attack in 2024. Half of the companies faced six or more attacks, an average of one incident every two months.
What Insider Threat Indicators Should You Look For?
Most insider threat warning signs involve suspicious behavior or abnormal patterns. If you know where to look, these glaring red flags can help you catch insider attacks in progress or even prevent them from happening in the first place.
1. Concerning Employee Actions
Changes in an employee’s behavior are one of the earliest indicators that you may have bad actors on your hands. Pay special attention to compliance violations involving:
- Regulatory standards (HIPAA, PCI DSS, etc.)
- Snooping into sensitive patient information or other private documents
- Disclosure of legal or financial communications, including to the media
- Unauthorized access to payment card information
Depending on the gravity of the situation, firing the individual may be the appropriate corrective action. Employees who lack integrity are more likely to betray you for financial gain if the opportunity presents itself.
2. Strange Email Behavior
Corporate email systems should be set up to track all inbound and outbound employee communications. Possible internal threat indicators include:
- Sharing any files or folders not related to the employee’s department
- Sending emails to non-corporate accounts (like “[email protected]”)
- Trying to attach large files (10 to 20 mb) to an email
- Adding dozens of smaller individual files
Ideally, you should disable email attachments completely unless required by role (such as billing department employees).
3. Abnormal File Activity
Pay close attention to user traffic to sensitive file storage locations. It should raise immediate red flags when employees download a large volume of company files to physical storage media, personal cloud-storage accounts, or third-party servers.
Insider threat detection systems should also flag strange file movements, like transferring sensitive documents from high-security folders to low-security or public storage locations. Excessive printing is also a warning sign.
4. Browsing Confidential Data Without a Legitimate Business Need
There’s no legitimate excuse for looking into private folders that aren’t related to the job department. When someone repeatedly attempts to access files they have no business seeing — like a secretary trying to peek at R&D documents — it’s more likely they’re testing the waters for an insider attack.
5. Accessing Sensitive System Areas After Business Hours
One of the most common insider threat risks is when users spend time on your system after hours without explicit permission. This behavior should trigger alerts, whether the login is online or with a physical security card. Be especially careful when the time doesn’t match up with the person’s normal work activity.
6. Suspicious Login Habits
Tracking user logins is a key part of cybersecurity awareness. Here’s what suspicious activity looks like:
- Multiple failed login attempts
- Multiple users trying to log in from the same network device
- One user logging in from different IP addresses
- Any VPN usage
- Mismatch between tracked device ID and user ID
It should set off major red flags if users request a password change after failing authentication five times or more.
7. Attempts To Disable or Tamper With Security Systems
Employees planning harmful actions frequently try to disable security and monitoring systems. Turning off antivirus software, modifying firewall settings, or disabling network logging tools are common insider threat indicators. These preventative measures are mandatory for HIPAA, PCI DSS, and ISO 27001 compliance, so even network admins have no business disabling them.
8. Installation of Potentially Harmful Software
Non-IT employees shouldn’t be allowed to install any software, period. The consequences should be especially severe for programs linked with data theft, like pen testing tools, encryption software, or password “cracking” apps. Not even IT personnel should use these tools outside of scheduled, supervised security audits.
9. Administrator-Level System Modifications
What if the people responsible for insider threats are the professionals you hired to keep your system safe? IT techs aren’t immune to causing deliberate attacks or accidental configuration errors. The following actions should trigger code red alerts:
- Changes to user privileges
- Elevation of access rights
- Creation of new user accounts
- Execution of user scripts
- Modifications of system processes
- Changing source code or dev environments
How can you tell legitimate IT activity from an insider attack? Harmful actions always aim to lower your system’s defenses, and they go against your cybersecurity framework.
10. Excessive Resource Consumption
Excessive network traffic or consumption of system resources are symptoms. They’re often caused by malicious scripts, automated data collection, large file uploads, or brute-force attacks.
How Do You Detect Potential Insider Threats and Mitigate Them?
Most of the time, a person doesn’t go from loyal employee to cybercriminal overnight. The better you understand your organization’s unique insider threat risk profile, the better you can protect yourself.
Insider Threat Risk Assessment
First, perform an insider-focused risk assessment. Identify worker groups that are most likely to become insider threats, such as:
- Disgruntled employees
- People who have been disciplined or denied promotions
- Individuals with heavy debt or hard financial situations at home
You should also consider which groups have the potential to cause the most damage, like IT administrators and management personnel.
Cybersecurity Policies, Processes, and Tools
Next, make sure your policies and cybersecurity practices align with modern frameworks. You can only detect abnormal employee behavior with a baseline to compare against.
If possible, invest in continuous network monitoring tools and advanced antimalware software. Today’s technology is exceptionally good at flagging anomalous behavior.
Finally, design your cybersecurity defenses around mitigation, not just prevention. With network segmentation and zero trust frameworks, you can limit how much access any one employee has independently, even executives.
Safeguard Your System Against Insider Threats
Robust cybersecurity frameworks (e.g., HITECH, ISO 27001, or NIST SP 800) give you a strong foundation, but they don’t catch every risk on their own. Compyl helps you move beyond checklist compliance by combining continuous monitoring with AI-guided insight, so threats are spotted early and handled quickly. Instead of juggling spreadsheets and manual reviews, your team gains a single platform that adapts to how you work by streamlining tasks, highlighting what matters most, and keeping you audit-ready without the heavy lift.
Discover how Compyl transforms risk management into a competitive advantage.
