Mimecast Study: 42% of Organizations Report Rise in Malicious Insider Threats Over Past Year

Core Insights - Mimecast's 9th annual State of Human Risk Report indicates a significant rise in malicious insider incidents, with 42% of organizations reporting an increase, matching the same percentage for negligent incidents, highlighting a shift in enterprise security concerns [1][2] Summary by Categories Malicious Insider Incidents - The percentage of organizations reporting increases in malicious insider incidents rose from 33% in 2024 to 42% in 2026, marking a nearly 10 percentage point increase over two years [2] - Organizations experience an average of six insider-driven incidents per month, with an estimated cost of $13.1 million per incident [2] Security Challenges - Insider risk is identified as a critical and underestimated threat, with attackers increasingly exploiting insiders to bypass perimeter defenses [3] - 91% of organizations face challenges in maintaining governance and compliance over communications data, which hampers their ability to effectively detect and respond to incidents [6][8] - 65% of organizations find security tool integration complicated, while attackers face no such constraints, leading to vulnerabilities in defense efforts [7] AI and Security - AI is seen as a force multiplier for both external attackers and malicious insiders, with 69% of security leaders believing AI attacks are inevitable within 12 months, yet 60% are not fully prepared [5][8] - The attack surface is expanding due to the use of email, GenAI platforms, and collaboration tools, but security strategies have not kept pace, with 38% of organizations relying solely on native security controls [4][8] Recommendations for Improvement - Organizations need to adopt a holistic strategy that integrates communication channels, collaboration platforms, and employee behaviors to address human risk effectively [11][12] - Successful integration of security measures can lead to faster threat remediation, improved visibility, and better compliance readiness, with 40% of organizations reporting such benefits [10]