What Is an Insider Threat? Definition, Examples, and Prevention

An insider threat is a cybersecurity risk that comes from someone within an organization, like an employee or contractor, who has access to sensitive information and may accidentally or intentionally put data at risk.

Who can pose an insider threat?

• Employees

• Contractors

• Vendors

• Executives

• Former employees

• Partners

Insider threats are particularly dangerous because insiders often bypass traditional security defenses due to their legitimate access. This makes detection and prevention more challenging.

Read on to learn more about different types of insider threats, common examples, indicators of an insider threat, and the threats that pose the greatest risk.

There are three types of insider threats: intentional, unintentional, and third-party threats. All three can cause significant harm to a network despite their differences in intent and execution.

Intentional insider threats involve individuals who deliberately misuse their authorized access to harm the organization. These malicious insiders might seek personal gain, financial profit, revenge, or aid external adversaries.

According to the CISA, hostile insiders "use technical means to disrupt or halt an organization's regular business operations, identify IT weaknesses, gain protected information, or otherwise further an attack plan via access to IT systems."

Unintentional insider threats occur when individuals inadvertently cause harm due to negligence, errors, or lack of awareness. These incidents happen when insiders fail to follow cybersecurity policies, fall victim to phishing emails, or neglect software updates.

Although unintentional, these actions can lead to significant compromises, such as data breaches.

Third-party threats involve external individuals or entities, such as vendors, contractors, or partners, who have been granted access to an organization's systems or data. Although not employees, these third parties can pose insider threats due to their level of access.

Because these third parties are trusted and integrated into the organization's operations, their access can be exploited by malicious actors. Third-party threats can be accidental or intentional and may involve collusion with external adversaries.

Supply chain attacks are an example of a third-party threat. Consider this scenario: an account takeover compromises a vendor, allowing criminals to use the account to trick employees into paying an invoice, downloading malware, or sharing sensitive data.

These types of attacks are particularly insidious because they are difficult to detect.

There have been many insider threat incidents in recent years. The 2024 Insider Threat Report by Cybersecurity Insiders revealed that 83% of organizations experienced at least one insider attack in the past year. Even more alarming, organizations that faced 11-20 insider attacks saw a fivefold increase compared to 2023, rising from 4% to 21% in just 12 months.

Some notable examples include:

• Reddit: In June 2023, Reddit experienced a security breach caused by an insider threat. An employee interacted with a fake internal site, granting attackers access to systems and compromising user data, including email addresses and credentials.

• Tesla: In May 2023, a German news outlet alerted Tesla to the acquisition of confidential company information. The investigation revealed that two former employees had violated Tesla's IT security and data protection policies by sharing the data with a media outlet.

• Cisco: A former engineer deleted 456 virtual machines and 16,000 Webex accounts, costing Cisco $2.4 million to repair.

Identifying potential insider threats requires monitoring for specific indicators of compromise. The following employee activities can signal a possible insider threat:

• Downloading unusually large amounts of data, especially at odd hours

• Accessing data unrelated to their job responsibilities

• Using external storage devices without authorization

• Downloading files with private information

• Emailing outside emails with sensitive data attached

• Unusual user geography changes

• Turning off encryption

• Violating cybersecurity policies

While these indicators don’t always mean an insider threat is blossoming, noting when employees access or use data unnecessarily for their role is important. Even if it is part of their job duties, behavioral analysis can help detect if unusual incidents are taking place.

Preventing insider threats involves implementing comprehensive security measures that address both technological and human factors. Organizations can take the following steps to mitigate the risk:

Establishing strict access controls is essential for safeguarding company data and systems. By enforcing the Principle of Least Privilege (PoLP), you can ensure that employees only have access to the information and systems necessary for their role, minimizing the risk of insider threats.

Behavioral analytics and robust monitoring are key to spotting potential threats early. By developing a strong monitoring system, you can detect unusual behavior before it becomes a serious issue.

Credential security is one of the most crucial areas of defense against insider threats. Strong password management, MFA, and regular vigilance can dramatically reduce the risk of unauthorized access to critical systems.

Employees play a vital role in protecting against insider threats. Regular education on security awareness can help them recognize potential risks and foster a security-conscious culture.

Insider threats are not limited to traditional attack methods. Attackers may directly solicit employees to participate in malicious activities, making it essential to stay ahead of emerging threats..

A strong offboarding procedure ensures that when employees leave, their access to company systems is promptly revoked, reducing the potential for post-departure threats.

Data Loss Prevention tools are essential for tracking and controlling the movement of sensitive information within and outside the organization. These tools help prevent malicious or accidental data leaks.

Preventing insider threats (or any cyberattack, really) is a journey, not a destination.

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