Quick Answer
Insider threats come from employees, contractors, or partners with legitimate access. Protection requires least privilege access, monitoring, DLP, offboarding controls, and culture. Technical controls alone aren't enough—you need to address why insiders become threats.
Quick answer: Insider threats come from employees, contractors, or partners with legitimate access. Protection requires least privilege access, monitoring, DLP, offboarding controls, and culture. Technical controls alone aren't enough—you need to address why insiders become threats.
Why Insider Threats Matter
The statistics:
- 60%+ of breaches involve insiders
- Average insider incident costs £500K+
- Detection takes 85+ days on average
- Hardest threats to detect (legitimate access)
Types of Insider Threats
Malicious insiders
Intentional harm:- Stealing data before leaving for competitor
- Sabotage by disgruntled employee
- Fraud for personal gain
- Selling access to criminals
- Termination notices
- Passed over for promotion
- Disciplinary issues
- Financial problems
- Ideological motivation
Negligent insiders
Accidental harm:- Falling for phishing
- Misconfiguring systems
- Losing devices
- Sending data to wrong recipient
- Using insecure practices
- Lack of training
- Poor security culture
- Excessive workload
- Inadequate tools
Compromised insiders
Unwitting accomplices:- Credentials stolen via phishing
- Account takeover
- Social engineering victims
- Malware on their devices
Prevention Controls
Least privilege access
Give minimum access needed:- Role-based access control
- Regular access reviews
- Remove access promptly when roles change
- Separate duties for sensitive functions
Strong authentication
Protect credentials:- MFA everywhere
- Privileged access management
- Session controls
- No shared accounts
Data Loss Prevention
Control data movement:- Monitor sensitive data
- Block unauthorised transfers
- Alert on suspicious activity
- Encryption requirements
Offboarding controls
Critical moment:- Immediate access revocation
- Return of devices
- Data preservation (legal hold)
- Exit interviews
- Monitor for data exfiltration before departure
Background checks
Know who you're hiring:- Pre-employment screening
- Ongoing checks for sensitive roles
- Contractor vetting
- Reference verification
Detection Controls
User behaviour analytics (UBA)
Detect anomalies:- Baseline normal behaviour
- Alert on deviations
- Access pattern analysis
- Data access anomalies
Activity monitoring
Know what's happening:- Privileged user monitoring
- File access logging
- Email monitoring (where legal)
- Cloud app activity
DLP alerts
Catch data leaving:- Sensitive data in emails
- Large uploads to personal cloud
- USB activity
- Print of sensitive documents
Endpoint monitoring
Device-level visibility:- EDR detecting suspicious tools
- USB device usage
- Screen capture attempts
- Unusual application use
The Human Element
Technical controls aren't enough.
Build security culture
- Clear policies employees understand
- Training on data handling
- Reporting without blame
- Leadership example
Address root causes
- Reasonable workloads
- Fair treatment
- Career development
- Open communication
Watch for warning signs
- Sudden behaviour changes
- Working unusual hours without cause
- Interest in areas outside role
- Bypassing security controls
- Complaints about being monitored
Legal Considerations
Monitoring employees has legal limits:
- GDPR applies to employee data
- Proportionality matters
- Transparency requirements
- Union considerations
- Reasonable expectation of privacy
What We Implement
Insider threat protection through:
- Access management - least privilege configuration
- DLP - Microsoft Purview for data protection
- Monitoring - activity logging and alerting
- Offboarding - automated access revocation
- Training - security awareness covering insider threats
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about detection and prevention.
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