Insider threat

Key takeaways

• Insider threats often involves individuals with legitimate access, including employees, contractors, vendors, and partners.
• These threats may be malicious, involving intentional misuse of authorized access or unintentional, resulting from negligence, errors, or lack of security awareness.
• Common insider threat scenarios include unauthorized data transfers, accidental data exposure, misuse of privileged access, and misusing user credentials.
• Real-world incidents at companies like Tesla and Microsoft demonstrate how both human error and deliberate actions can lead to large-scale data exposure.
• Insider threats are difficult to detect because the activity often appears normal, coming from trusted users operating within their access privileges.
• Early warning signs of insider threat includes unusual data access patterns, spikes in data transfers, suspicious user behavior, and activity from stale or orphaned accounts.
• Effective prevention requires a combination of user awareness, strict access controls such as least privilege, continuous monitoring, and enforcing strong data protection standards.
• A proactive and continuous security strategy is essential to identify, mitigate, and prevent insider threats before they escalate.

What is an insider threat?

Insider threats are security risks that arise from the people within organizations. In fact, nearly 71% of organizations feel moderately vulnerable to insider threats. They are associated with not just current employees but also with former employees, vendors, and partners. Insider threats can result in devastating data theft, leak, or exposure. However, not all of these incidents are deliberate. Employees or business associates can also cause security incidents unintentionally, either through careless actions or by inaction.

Since insider attacks originate from individuals within the organization, they are difficult to detect and respond to. Read on to learn more about these threats.

Insider threat examples

The following scenarios illustrate how individuals with internal access can misuse organizational systems and data, either intentionally or unintentionally.

• A sales representative uploads a complete list of client contacts and pricing strategies to their personal cloud storage a week before resigning to join a competitor.
• An HR administrator inadvertently sends a spreadsheet containing employee salaries and Social Security numbers to an all-staff email alias instead of just the finance department.
• A marketing manager uploads a database of customer emails to a free, online GenAI tool to help with data cleaning, inadvertently exposing sensitive data to an unverified external server.
• A remote developer uses an unsecured public Wi-Fi network, allowing an attacker to intercept the login session and gain "trusted" access to the production environment.
• A disgruntled systems administrator creates a hidden administrative account with a generic name to maintain access to the network even after their employment is terminated

Famous insider threat cases

From accidental exposure to deliberate data theft, internal risks have played a key role in major incidents at Microsoft, Tesla, and Proofpoint. Here are a few examples of how these threats unfolded.

• Tesla misuse of access privileges: Two former employees misused their valid credentials to exfiltrate 100GB of confidential data, including personal records of over 75,000 employees. They bulk-downloaded more than 23,000 files from internal service databases that lacked real-time monitoring for large-scale data transfers. The breach was only discovered after the data had been moved to personal devices and shared externally.
• Microsoft data exposure caused by human error: A significant Microsoft data exposure, rooted in human error, occurred when a researcher inadvertently leaked 38TB of sensitive data on GitHub. By utilizing an over-permissive shared access signature token to share AI models, the researcher granted full control over an internal storage account rather than the intended read-only access. This misconfiguration exposed private backups, employee credentials, and internal communications to the public.
• Proofpoint departing employee risk: In 2021, a departing employee exploited their active access to download proprietary sales materials and competitive intelligence before joining a rival company. The data was copied to external storage without triggering alerts, as the activity appeared to come from a trusted user. The breach was only identified during a post-resignation investigation.

Types of insider threats

Insider threats can be classified based on the intention or motive behind them. They are either caused by rogue employees harboring malicious intent or by unwitting actions of a negligent employee.

Malicious intent of insiders can be driven by:

• Dissatisfaction with current employers or with organizational policies.
• Corporate espionage or for financial gains.
• Influence of hackers or external entities who convince insiders to sabotage the organization.

Unintentional security risks created by employees include:

• Unauthorized data transfer outside the organization for personal convenience.
• Falling victim to phishing sites that imitate formal websites.
• Side-stepping corporate security policies on removable media usage, accessing unwanted websites, etc.

Challenges in detecting insider threats

While 97% of security professionals are concerned about inadvertent insider threats, these risks remain the hardest to manage because they originate within the "circle of trust." This internal position creates several specific obstacles to effective detection:

• Misuse of legitimate access: Insiders use their own legitimate usernames and passwords, making their actions look like standard tasks. Systems often fail to distinguish between an employee accessing a file for a project and an employee accessing that same file to steal it.
• Lack of a malware signature: External hackers use recognizable viruses or code that a security software can flag while insiders use legitimate tools like email, cloud storage, and USB drives. Without a "virus" to identify, there is no automatic alarm to trigger.
• Low and slow data theft: Security alerts are usually set to trigger when massive amounts of data move at once. A strategic insider can bypass these tripwires by stealing very small amounts of information over a long period, staying below the threshold of most monitoring tools.
• Visibility gaps from shadow IT: Employees frequently use personal apps, GenAI tools, or private cloud accounts to work faster. This creates a blind spot for the company; IT cannot secure or monitor data once it moves into an application or device that the organization doesn't control.
• Privacy and workplace trust: Heavy surveillance can hurt company culture and lead to legal or privacy concerns. Organizations must find a way to monitor behavior enough to stay safe without creating a "spy-like" environment that lowers morale and increases resentment.

Understanding these hurdles in detecting insider threat is the first step toward moving from a reactive to a proactive security posture.

Insider threat indicators

It is essential to spot telltale signs of an insider attack as early as possible. Be on the lookout for:

• Increase in security incidents

  Track and inspect critical systems and processes in your organization for vulnerabilities. Spot and investigate the source of every incident to eliminate even the slim possibility of an insider attack.

• Suspicious employee behavior

  Spot suspicious behavior of employees such as disengagement at work and lack of collaboration. Monitor these employees' activities such as unauthorized file accesses or changes with more caution.

• Use of orphaned or stale user accounts

  Locate and roll back the privileges and access rights of former employees. Isolate and analyze any orphaned user accounts showing activity.

• Suspicious data transfer activities

  Be on alert for sudden spikes in data transfer activities. Identify who transferred the file, why, and when to investigate the action further, and determine if it was necessary.

• Overexposed critical data

  Periodically review what and how much of your critical data is accessible to vendors and third parties. Ensure the transfer of data to such entities is safe and secure.

• Unusual data access patterns

  Monitor files accessed during non-business hours or in high volumes. Investigate data requests that exceed job requirements.

Insider threat prevention

Pursue a holistic approach to effectively defend business-critical information from insider attacks. Be diligent in detecting early signs and safeguarding organizational data to avoid data loss.

Evaluate data privacy policies implemented in your organization periodically. Review what data is in use, where, and how it flows in and out of the authorized network. Fighting insider threats is a continuous process. Ask yourself the following questions when considering data security strategies:

• Are you implementing the principle of least privilege throughout your organization?
• Are your employees and partners well informed and educated on security risks?
• Do you have data discovery software to find instances of sensitive data to secure their use and access?
• Do you review unusual user activity?
• Do you have insider threat detection software for prompt detection of suspicious file activity?

If the answer to even one of the above questions is "no," it's time to reevaluate your data security strategies against internal threats. Employ a combination of physical controls and software tools to shield your organization from data loss. Focus on constantly monitoring data, users, and security incidents, so you can take swift remedial action when needed.

Frequently asked questions