Insider Threats Drive Rising Costs of Data Breaches, Reports Highlight Risks from Employee Departures
A growing body of research underscores the severe financial and operational risks posed by insider threats particularly when employees leave an organization. According to IBM’s Cost of a Data Breach Report 2025, the global average cost of a data breach reached $4.44 million, with malicious insider attacks incurring even higher losses at $4.92 million. Even unintentional insider errors carried a significant price tag, averaging $3.62 million.
The risk of data loss escalates during employee departures, whether voluntary or involuntary. Verizon’s 2025 Data Breach Investigations Report found that privilege misuse where insiders abuse legitimate access remains a leading cause of breaches, driven by financial motives, espionage, or personal grievances. While not all incidents are malicious, many stem from misunderstandings over data ownership, weak bring-your-own-device (BYOD) policies, or employees transferring work-related materials to personal devices.
Voluntary resignations introduce unique challenges. Some departing employees may unknowingly retain sensitive data, while others deliberately exfiltrate proprietary information such as client lists, source code, or product formulas to gain a competitive edge at a new employer. The risk intensifies with involuntary terminations. Cyberhaven’s 2024 Insider Risk Report revealed a 720% surge in data exfiltration in the 24 hours preceding a layoff, as disgruntled employees may sabotage systems, sell access to hackers, or leak confidential data.
The nature of the threat varies by role, with high-level access increasing potential damage. Common targets of exfiltration include customer data, intellectual property, and design files, often transferred via personal cloud storage, removable media, or generative AI tools. Remote employees are more likely to use unsecured methods like Bluetooth or AirDrop, further complicating detection.
With insider threats accounting for a substantial share of breaches, organizations face a dual challenge: mitigating both accidental exposure and deliberate misuse of access particularly during periods of workforce transition.
Source: https://www.techtarget.com/searchdatamanagement/tip/How-to-cut-data-loss-risks-when-employees-leave
Cyberhaven TPRM report: https://www.rankiteo.com/company/cyberhaven
Verizon TPRM report: https://www.rankiteo.com/company/verizon
"id": "vercyb1771022282",
"linkid": "verizon, cyberhaven",
"type": "Breach",
"date": "1/2025",
"severity": "85",
"impact": "4",
"explanation": "Attack with significant impact with customers data leaks"{'attack_vector': ['Privilege Misuse', 'Data Exfiltration'],
'data_breach': {'data_exfiltration': '720% surge in data exfiltration in the '
'24 hours preceding a layoff',
'sensitivity_of_data': ['High'],
'type_of_data_compromised': ['Customer Data',
'Intellectual Property',
'Design Files',
'Client Lists',
'Source Code',
'Product Formulas']},
'description': 'A growing body of research underscores the severe financial '
'and operational risks posed by insider threats, particularly '
'when employees leave an organization. Insider threats, '
'including privilege misuse and data exfiltration during '
'employee departures, are leading causes of data breaches with '
'significant financial and operational impacts.',
'impact': {'data_compromised': ['Customer Data',
'Intellectual Property',
'Design Files',
'Client Lists',
'Source Code',
'Product Formulas'],
'financial_loss': '$4.44 million (global average), $4.92 million '
'(malicious insider attacks), $3.62 million '
'(unintentional insider errors)'},
'lessons_learned': 'Insider threats, particularly during employee departures, '
'pose significant financial and operational risks. '
'Organizations must address both accidental exposure and '
'deliberate misuse of access, especially during workforce '
'transitions.',
'motivation': ['Financial Gain',
'Espionage',
'Personal Grievances',
'Competitive Advantage'],
'post_incident_analysis': {'root_causes': ['Privilege misuse',
'Data exfiltration during employee '
'departures',
'Weak BYOD policies',
'Unsecured data transfer methods']},
'recommendations': ['Strengthen BYOD policies',
'Clarify data ownership guidelines',
'Monitor data exfiltration during employee departures',
'Enhance detection of unsecured data transfer methods',
'Implement stricter access controls for high-level roles',
'Educate employees on data security best practices'],
'references': [{'source': 'IBM’s Cost of a Data Breach Report 2025'},
{'source': 'Verizon’s 2025 Data Breach Investigations Report'},
{'source': 'Cyberhaven’s 2024 Insider Risk Report'}],
'threat_actor': ['Insiders (Employees, Former Employees)'],
'title': 'Insider Threats Drive Rising Costs of Data Breaches',
'type': ['Insider Threat', 'Data Breach'],
'vulnerability_exploited': ['Weak BYOD Policies',
'Misunderstandings over Data Ownership',
'Unsecured Data Transfer Methods']}