Insider Threat Investigation | Decripte Security

Insider threats pose unique risks due to the combination of legitimate access, knowledge of systems, and diverse motivations. Detecting and investigating insider threats requires a specialized approach that balances security with employee privacy.

Types of Insider Threats

Malicious Insider: Acts intentionally to cause harm, steal information, or sabotage systems. Motivations include financial gain, revenge, ideology.

Negligent Insider: Fails to follow security policies, makes mistakes that expose the company to risk. Examples: clicking phishing links, using weak passwords, sharing confidential information.

Third Parties: Partners, suppliers, service providers with access to internal systems. They can be attack vectors or act maliciously.

Former Employees: Access not revoked after offboarding, active accounts with improper privileges. Risk of sabotage or data theft.

Behavioral Indicators

Abnormal Data Access: Accessing information outside the scope of one's role, at unusual times, or in large volumes.

Unusual File Copying: Transferring large amounts of data to removable devices, personal cloud storage, or external email.

Anomalous Network Activity: Connecting to suspicious servers or sites, using unauthorized VPNs, attempting to bypass security controls.

Policy Violations: Disregarding security rules, attempting to circumvent controls, negligent behavior with confidential information.

Behavioral Changes: Irritability, stress, dissatisfaction, financial or personal problems.

Data Sources for Detection

Access Logs: Authentication, file access, databases, applications.

Network Logs: Network traffic, connections, bandwidth usage.

Endpoint Logs: User activity, processes, files, connected devices.

Email Logs: Sending, receiving, attachments, clicked links.

DLP Logs: Data leakage detection, copying of confidential files.

HR Data: Employee history, performance reviews, complaints, internal investigations.

UEBA - User and Entity Behavior Analytics

UEBA uses machine learning to analyze the behavior of users and entities (devices, applications) and detect anomalies that indicate an insider threat.

Behavior Baseline: Establishes normal activity patterns for each user and entity.

Anomaly Detection: Identifies deviations from the baseline, such as access to unusual data, atypical times, abnormal data transfers.

Risk Prioritization: Assigns risk scores to users and entities based on detected anomalies.

SIEM Integration: Sends alerts to the SIEM for investigation and incident response.

Data Loss Prevention (DLP)

DLP monitors and controls the flow of confidential information to prevent data leakage.

Content Awareness: Analyzes the content of files, emails, and network traffic to identify sensitive information (credit card data, personal information, trade secrets).

Policy Enforcement: Applies security policies to block, alert, or log activities that violate the rules.

Endpoint DLP: Controls file copying to removable devices, cloud storage, printing.

Network DLP: Monitors network traffic to detect data exfiltration via email, web, FTP.

Investigation Process

1. Alert: Receipt of an alert from UEBA, DLP, SIEM, or another source.

2. Triage: Initial assessment of the alert to determine whether it is a false positive or a real incident.

3. Evidence Collection: Collection of logs, endpoint data, emails, access records.

4. Analysis: Analysis of the evidence to determine the scope of the incident, the impact, and the cause.

5. Containment: Actions to prevent the incident from spreading or causing further damage (disable account, isolate device, revoke access).

6. Remediation: Fixing the vulnerabilities that enabled the incident, strengthening security controls.

7. Disciplinary/Legal Actions: Take appropriate measures against the employee involved, if applicable.

Legal and Ethical Aspects

Privacy: Balance security with employee privacy, avoiding excessive or invasive monitoring.

Transparency: Inform employees about the monitoring policies and the risks of insider threats.

Discrimination: Avoid decisions based on race, religion, gender, or other protected characteristics.

Due Process: Ensure that employees have the opportunity to defend themselves before taking disciplinary measures.

Compliance: Comply with data protection laws and regulations (LGPD, GDPR).

Policies and Procedures

Information Security Policy: Define clear rules on the use of company resources, data access, protection of confidential information.

Acceptable Use Policy: Establish limits for the use of the internet, email, social media.

Password Policy: Require strong passwords, regular changes, multi-factor authentication.

DLP Policy: Define rules for protecting confidential data, controlling copies and transfers.

Investigation Procedure: Describe the steps to be followed in the event of a suspected insider threat.

Training and Awareness

Security Training: Educate employees about the risks of insider threats, how to identify phishing, how to protect passwords, how to report incidents.

Phishing Simulations: Test employees' ability to identify malicious emails.

Regular Communication: Send newsletters, intranet posts, reminders about security.

Security Culture: Create an environment where security is valued and employees feel comfortable reporting incidents.

Continuous Monitoring

Log Monitoring: Analyze access, network, and endpoint logs to detect suspicious activity.

Email Monitoring: Check for confidential information being sent outside the company.

Removable Device Monitoring: Control file copying to USBs, external HDDs.

Behavioral Analysis: Use UEBA to identify anomalies in user behavior.

Incident Response

Incident Response Plan: Define the steps to be followed in the event of an insider threat incident.

Incident Response Team: Designate those responsible for each stage of the process.

Communication: Inform relevant stakeholders about the incident.

Remediation: Fix the vulnerabilities that enabled the incident.

Disciplinary/Legal Actions: Take appropriate measures against the employee involved.

Supporting Technologies

SIEM: Centralizes logs from various sources for analysis and detection of incidents.

UEBA: Analyzes the behavior of users and entities to detect anomalies.

DLP: Monitors and controls the flow of confidential information.

CASB: Protects data in cloud applications.

EDR: Detects and responds to threats on endpoints.