Malicious Insider Threats Anticipated as Major Challenge for CISOs in 2025, Experts Warn

In an increasingly chaotic employment landscape, the risk posed by malicious insiders is expected to surge this year, casting a significant shadow over Chief Information Security Officers (CISOs). Allie Mellen, a Forrester analyst specializing in information security, advises that heightened economic instability and job uncertainty can breed resentment among former and current employees, presenting unique threats to organizations. This concern is especially pertinent as countless companies, including prominent U.S. government agencies, contend with mass layoffs of skilled IT personnel, thereby raising the risks associated with insider threats.
Mellen highlights that potential insider threats will emerge not only from disgruntled ex-employees seeking revenge but also from current staff who may feel undervalued or threatened. With this backdrop, a disturbing incident involving Ohio-based Eaton Corp. underscores the seriousness of these threats. The company experienced system failures caused by a “kill switch” hidden in code left by a senior developer who was terminated, demonstrating the potential damage a disgruntled insider can inflict.
This case reflects a broader trend in which insiders, when motivated by resentment or financial incentive, exploit the access and knowledge they have acquired to compromise their employer’s systems. Following the release of federal criminal indictments against the former Eaton employee, it was revealed that he had researched methods to escalate privileges and obstruct recovery efforts post-termination, amassing hundreds of thousands in damages for his employer.
Analysis from the 2024 Verizon Data Breach Report reveals that a significant portion of data breaches are linked to insider actions characterized by privilege misuse. In fact, of the 30,458 security incidents evaluated, nearly 3% were attributed directly to employee betrayal, often driven by motivations such as financial gain or revenge. An evident connection between privilege misuse and intentional sabotage underscores the need for companies to remain vigilant against the actions of their insiders during times of transition.
Business owners are advised to take proactive measures when addressing potential insider threats. The Cybersecurity and Infrastructure Security Agency recommends conducting thorough risk assessments before, during, and after employee separations to mitigate the potential for adverse reactions. Different types of employee departures, such as layoffs or separations due to serious performance issues, can pose varying levels of risk, highlighting the importance of tailored security strategies to safeguard organizational resources.
The growing scenario further complicates matters as insiders may be approached by external criminal organizations. Cybercriminals, including ransomware groups, are known to exploit discontent among employees, offering lucrative deals in exchange for sensitive information. Forrester’s Mellen points out that these situations can develop quickly, with unsuspecting employees being lured into compromise by offers that may seem harmless or profitable.
As organizations navigate through uncertainty, security leaders must prioritize building robust defenses against insider threats while simultaneously addressing the well-being of their employees. Effective security measures, employee awareness programs, and ongoing training can foster an environment where trust is balanced with vigilance, allowing businesses to thrive amidst potential threats.
By recognizing the dynamics at play and implementing strong security measures, business leaders can prepare to mitigate the risks associated with malicious insiders and protect their organizations against significant threats. This increased awareness prepares them to identify, respond to, and prevent scenarios that could jeopardize their operational integrity and financial stability.