Insider threats are one of the most dangerous and difficult-to-detect security risks. These threats come from individuals within the organization — employees, contractors, or partners — who have legitimate access but misuse it maliciously or negligently.
Addressing insider threats—whether malicious or accidental—requires a nuanced and strategic approach within an Incident Response (IR) framework. Unlike external attacks, insider threats originate from individuals with legitimate access, making them harder to detect and more damaging if mishandled.
Here’s a breakdown of Insider Threats and how Incident Response solutions can tackle them effectively.
What Is an Insider Threat?
An insider threat is any threat to an organization’s security posed by people with authorized access.
Types of Insider Threats:
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Malicious Insiders: Intentionally steal, damage, or expose data (e.g., a disgruntled employee leaking trade secrets).
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Negligent Insiders: Unintentionally cause harm (e.g., clicking a phishing link or misconfiguring permissions).
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Compromised Insiders: Accounts taken over by external attackers (e.g., credential theft via phishing).
Why Insider Threats Are Hard to Detect
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Use legitimate access to perform harmful actions.
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May not trigger traditional security alerts.
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Activity may look “normal” in many cases (e.g., downloading files, sending emails).
How IR Teams Can Respond to Insider Threats
Here’s how incident response services and processes adapt to address insider risks:
1. Establish an Insider Threat Detection Program
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Combine HR, legal, and IT security teams.
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Use User and Entity Behavior Analytics (UEBA) to detect anomalies like:
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Data downloads at odd hours
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Logins from unusual locations
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Sudden privilege escalations
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2. Create Insider-Focused Playbooks
Tailor IR playbooks for:
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Data exfiltration
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Abuse of privileged access
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Suspicious user behavior
Playbooks should include:
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Behavior baseline comparison
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HR/legal coordination steps
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Forensic data collection and preservation
3. Use Specialized Tools
🛠️ Key Tech Capabilities:
| Tool Type | Examples | Role in Insider Threat IR |
|---|---|---|
| SIEM/XDR | Splunk, NetWitness, Microsoft Sentinel, CrowdStrike | Log correlation and alerting |
| DLP | Symantec DLP, Forcepoint | Detect data leaks or transfers |
| UEBA | Exabeam, Varonis, Microsoft Defender, NetWitness | Detect behavioral anomalies |
| Insider Risk Tools | Microsoft Purview, Code42 Incydr | Monitor file movement, comms, and intent |
| Endpoint Monitoring | EDR tools (NetWitness, SentinelOne, Carbon Black) |
4. Deep-Dive Forensics
During incident response:
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Audit file access and transfers (USB, cloud sync, FTP)
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Review email logs (e.g., sending sensitive info externally)
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Capture browser history and screen activity
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Analyze chat logs, especially from Slack, Teams, etc.
5. Legal & HR Coordination
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Insider investigations often have legal implications.
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Maintain chain of custody.
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Ensure compliance with privacy and labor laws.
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Consider involving HR before engaging with suspected insiders.
Organizational Considerations
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HR + Legal Involvement: Insider incidents often require HR/legal input for compliance and disciplinary action.
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Privacy Balance: Monitor ethically and within legal constraints (e.g. GDPR, HIPAA).
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Cultural Awareness: Over-surveillance can harm trust; use transparent policies and informed consent.
Post-Incident Actions
| Action | Purpose |
|---|---|
| Access reviews | Remove unnecessary privileges |
| Policy & awareness updates | Educate staff on data handling & risks |
| Behavioral monitoring tuning | Update detection logic for similar patterns |
| HR/legal follow-up | Discipline, legal action, or employee exit |
| ASI sync | Update attack surface view with internal asset risks |
Insider Threat IR Response Flow
Example:
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Alert: Employee uploads 10GB to Dropbox
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Incident response: Verifies role, file types, intent
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Contain: Disable account access
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Eradicate: Revoke permissions, block cloud sync
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Recover: Alert affected teams, patch controls
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Learn: Add Dropbox to DLP watchlist, educate employees
Final Thought
Insider threats require both technical and human investigation.
Incident Response services teams must be equipped to investigate discreetly, coordinate broadly, and act surgically.