--- name: performing-insider-threat-investigation-508e46889109 description: 'Investigates insider threat incidents involving employees, contractors, or trusted partners who misuse authorized access to steal data, sabotage systems, or violate security policies. Combines digital forensics, user behavior analytics, and HR/legal coordination to build an evidence-based case. Activates for requests involving insider threat investigation, employee data theft, privilege misuse, user behavior anomaly, or internal threat detection. ' domain: cybersecurity subdomain: incident-response tags: - insider-threat - user-behavior-analytics - data-exfiltration - privilege-misuse - DFIR mitre_attack: - T1078 - T1048 - T1567 - T1114 version: 1.0.0 author: Krishna Kumar (xalgord) license: Apache-2.0 nist_csf: - RS.MA-01 - RS.MA-02 - RS.AN-03 - RC.RP-01 --- # Performing Insider Threat Investigation ## When to Use - DLP (Data Loss Prevention) alerts on large data transfers to personal cloud storage or USB devices - User behavior analytics (UBA) detects anomalous access patterns for a user account - HR reports a departing employee suspected of taking proprietary information - A privileged user is observed accessing systems outside their job function - Whistleblower or coworker report alleges policy violations or data theft **Do not use** for external attacker investigations where compromised credentials are used without insider collusion; use standard incident response procedures instead. ## Detection Gaps & Validation - **Low-and-slow beats threshold alerts:** the most-missed insider drips data out under DLP limits — 20-50MB/day to personal webmail or a sanctioned cloud tenant over weeks, rather than one big USB dump. Baseline each user's 3-6 month normal (volume, destinations, hours) and alert on sustained deviation, not a single large transfer. - **Authorized access ≠ authorized use:** insiders use legitimate credentials, so signature/IOC detection sees nothing. Validate intent by correlating *what* was accessed against job function (UEBA peer-group anomaly), access timing (after-hours/post-resignation), and staging behavior (mass reads, zip/rar creation, renaming to innocuous extensions). - **Cover every exfil vector, not just the alerting one:** USB, personal webmail, OneDrive/GDrive/Dropbox sync clients, browser uploads, print jobs, screenshots, AirDrop/Bluetooth, and phone-camera capture of screens. A clean DLP log only rules out the channels DLP inspects — confirm with endpoint sync-client logs, print logs, and badge data. - **Cross-corroborate before accusing:** pair behavioral anomaly with content evidence (the actual file, its classification) and a timeline (Git clone logs, USN Journal, cloud activity API). One signal is a lead; a corroborated timeline is a case. Compare against the documented baseline to avoid flagging a genuinely busy quarter as theft. - **FP tuning / preserve admissibility:** scope monitoring to legal-approved subjects and exclude sanctioned bulk workflows (backups, data-migration roles). Don't tip off the subject, hash and chain-of-custody all evidence, and image the endpoint before the last day — an untested assumption of guilt collapses without preserved, reproducible evidence. ## Prerequisites - Legal counsel approval before initiating any monitoring or investigation of an employee - HR partnership with defined investigation procedures and employee privacy guidelines - DLP platform with content inspection and policy enforcement (Symantec DLP, Microsoft Purview, Digital Guardian) - User behavior analytics platform (Microsoft Sentinel UEBA, Exabeam, Securonix) - Forensic imaging capability for endpoint examination - Chain of custody procedures for evidence that may be used in legal proceedings - Clear authority and scope documentation approved by legal and HR ## Workflow ### Step 1: Receive and Validate the Allegation Document the initial report and validate before proceeding: - Record the source of the allegation (DLP alert, UBA detection, HR referral, manager report) - Confirm with legal counsel that the investigation is authorized - Define the investigation scope: what activity is being investigated, time period, systems involved - Establish the investigation team: security, legal, HR (never investigate alone) - Create a restricted case file accessible only to the investigation team ``` Investigation Authorization: ━━━━━━━━━━━━━━━━━━━━━━━━━━━ Case ID: INV-2025-042 Subject: [Employee Name] - [Title] - [Department] Allegation: Unauthorized transfer of proprietary data to personal cloud storage Reported By: DLP system alert + manager concern Legal Approval: [Counsel Name] - 2025-11-15 HR Liaison: [HR Name] Scope: File access and transfer activity from 2025-10-01 to present Systems in Scope: Workstation, email, cloud storage, VPN, DLP logs ``` ### Step 2: Collect Evidence Covertly Gather evidence without alerting the subject to the investigation: **Log-Based Evidence (non-intrusive):** - DLP logs: file transfers, policy violations, content matches - Cloud access logs: SharePoint, OneDrive, Google Drive activity - Email logs: messages to personal accounts, large attachments, forwarding rules - VPN and authentication logs: access times, locations, devices - Badge access logs: physical access patterns - Print logs: large print jobs of sensitive documents - USB device connection logs: device type, serial number, connection times **User Activity Monitoring (requires legal approval):** - Screen capture or session recording (only if legally authorized and documented) - Keystroke logging (jurisdiction-dependent, requires explicit legal approval) - Network traffic capture for the subject's workstation **Endpoint Forensics (if warranted by evidence):** - Create forensic image of the subject's workstation - Analyze browser history, download history, and installed applications - Examine deleted files and Recycle Bin contents - Review cloud sync application logs (Dropbox, Google Drive desktop client) ### Step 3: Analyze User Behavior Patterns Build a behavioral profile comparing normal vs. anomalous activity: ``` Behavioral Analysis: ━━━━━━━━━━━━━━━━━━ Normal Baseline (6-month average): - Login time: 08:30-09:00 weekdays - Files accessed: 15-25 per day (marketing department files) - Email volume: 45 sent, 80 received per day - Data transferred: 50MB per day average - USB usage: None Investigation Period (last 30 days): - Login time: 22:00-02:00 (after hours, multiple occasions) - Files accessed: 200+ per day (finance, engineering, executive files) - Email volume: 120 sent per day (30% to personal gmail) - Data transferred: 2.5GB per day average - USB usage: 3 unique devices connected (Kingston DataTraveler) - Print jobs: 847 pages (competitor analysis, customer lists, source code) Anomaly Score: 94/100 (Critical) ``` ### Step 4: Reconstruct the Activity Timeline Build a chronological timeline of the subject's actions: ``` Timeline of Activity: 2025-10-15 Subject submits resignation (2-week notice) 2025-10-16 First after-hours login at 23:15, accessed engineering Git repository 2025-10-17 USB device (Kingston DT 64GB) first connected at 23:30 2025-10-18 DLP alert: 450 files copied to USB, including CAD drawings 2025-10-19 200+ emails forwarded to personal Gmail account 2025-10-20 Google Drive desktop client installed, syncing corporate SharePoint 2025-10-22 Accessed executive SharePoint site (not normally accessed) 2025-10-25 Second USB device connected, 2.1GB transferred 2025-10-28 Print job: 847 pages including customer contact database ``` ### Step 5: Assess Impact and Determine Response Evaluate the severity and coordinate the response with HR and legal: **Impact Assessment:** - What data was accessed or exfiltrated (classification level, business impact) - Was the data shared externally (competitors, public, personal storage) - Regulatory implications (PII, PHI, financial data, export-controlled) - Contractual implications (NDA violations, IP assignment agreements) - Potential financial damage to the organization **Response Options (determined by legal and HR):** - Confront the subject with evidence during an interview (HR-led) - Terminate employment and revoke all access immediately - Pursue civil litigation for breach of NDA or trade secret theft - Refer to law enforcement for criminal prosecution (theft of trade secrets, CFAA violation) - Negotiate a settlement with return/destruction of data ### Step 6: Preserve Evidence for Legal Proceedings Ensure all evidence meets legal admissibility standards: - Maintain strict chain of custody for all physical and digital evidence - Document all analysis steps in detail (reproducible by another examiner) - Hash all evidence files and maintain an integrity log - Store evidence in a secure, access-controlled repository with audit logging - Retain evidence per legal hold requirements (do not destroy during active investigation or litigation) ## Key Concepts | Term | Definition | |------|------------| | **Insider Threat** | Risk posed by individuals with authorized access who intentionally or unintentionally cause harm to the organization | | **User Behavior Analytics (UBA)** | Technology that analyzes user activity patterns to detect anomalies indicating potential insider threats | | **Data Loss Prevention (DLP)** | Technology that monitors, detects, and blocks unauthorized transfer of sensitive data outside the organization | | **Legal Hold** | Directive to preserve all relevant evidence and suspend normal document destruction policies during an investigation | | **Need to Know** | Information access principle restricting insider threat investigation details to only authorized team members | | **Exfiltration Vector** | Method used to move data outside the organization: USB, email, cloud storage, print, screen capture, photography | ## Tools & Systems - **Microsoft Purview (formerly Compliance Center)**: Insider risk management, DLP, eDiscovery, and content search - **Exabeam / Securonix**: User and entity behavior analytics (UEBA) platforms for anomaly detection - **Digital Guardian**: DLP and insider threat detection platform with endpoint agent - **Magnet AXIOM**: Digital forensics platform supporting endpoint, cloud, and mobile evidence analysis - **Relativity**: eDiscovery platform for legal review of collected evidence in insider threat cases ## Common Scenarios ### Scenario: Departing Engineer Exfiltrating Source Code **Context**: A senior software engineer with access to critical repositories submits a two-week resignation notice. The engineering manager reports that the engineer has been working unusual hours and downloading large amounts of code. **Approach**: 1. Obtain legal authorization to investigate before taking any action 2. Pull Git access logs showing repository clones and downloads for the past 60 days 3. Review DLP logs for USB device connections and large file transfers 4. Check email gateway for messages with code attachments sent to personal accounts 5. Analyze browser history for personal cloud storage uploads 6. Image the workstation forensically before the employee's last day 7. Present findings to legal and HR for determination of next steps **Pitfalls**: - Investigating without legal counsel authorization (may violate employee privacy rights) - Alerting the subject to the investigation before evidence is preserved - Not preserving the workstation before the employee's departure date - Assuming all after-hours access is malicious without comparing to the employee's historical baseline - Failing to check personal mobile devices that may have accessed corporate cloud services ## Output Format ``` INSIDER THREAT INVESTIGATION REPORT ===================================== Case ID: INV-2025-042 Classification: CONFIDENTIAL - Need to Know Only Subject: [Name Redacted] - Senior Engineer Investigation Period: 2025-10-01 to 2025-10-28 Investigator: [Name] Legal Counsel: [Name] HR Liaison: [Name] ALLEGATION Unauthorized exfiltration of proprietary source code and customer data following resignation submission. EVIDENCE SUMMARY 1. Git logs: 47 repositories cloned (vs. baseline of 3) 2. USB transfers: 4.6 GB across 3 unique devices over 12 sessions 3. Email: 200+ emails with attachments forwarded to personal Gmail 4. Cloud: Google Drive sync client installed, syncing corporate files 5. Print: 847 pages including customer contact database 6. Physical access: After-hours badge access on 8 of 12 workdays BEHAVIORAL ANALYSIS [Baseline vs. anomalous activity comparison] IMPACT ASSESSMENT Data Classification: Confidential (source code, customer PII) Estimated Volume: 7.2 GB exfiltrated Regulatory Impact: Potential GDPR notification (customer PII) Business Impact: Competitive advantage at risk TIMELINE [Chronological event listing] RECOMMENDATIONS 1. [Legal/HR decision on employment action] 2. [Evidence preservation actions] 3. [Regulatory notification assessment] 4. [Access control improvements] ``` --- Source attribution: xalgord Original project: https://github.com/xalgord/xalgorix/blob/cec44d71b1d998208e1e2091982d0ee2f928041f/internal/tools/skills/data/incident-response/performing-insider-threat-investigation/SKILL.md License: Apache-2.0 License information: https://www.apache.org/licenses/LICENSE-2.0 Original upstream instructions; downloaded from Dave AI. ## Upstream license notice Apache License Version 2.0, January 2004 http://www.apache.org/licenses/ TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 1. Definitions. "License" shall mean the terms and conditions for use, reproduction, and distribution as defined by Sections 1 through 9 of this document. "Licensor" shall mean the copyright owner or entity authorized by the copyright owner that is granting the License. "Legal Entity" shall mean the union of the acting entity and all other entities that control, are controlled by, or are under common control with that entity. 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See the License for the specific language governing permissions and limitations under the License. # Dave AI resource metadata Creator / publisher: xalgord Original project: https://github.com/xalgord/xalgorix/blob/cec44d71b1d998208e1e2091982d0ee2f928041f/internal/tools/skills/data/incident-response/performing-insider-threat-investigation/SKILL.md Attribution basis: Source repository record Fields of work: Development & Engineering, Human Resources, Legal Roles: Compliance Officer, HR Generalist, Legal Operations, Security Engineer Specialties: Specialty not specified Tools: Dlp Platforms, Uba Platforms Country applicability: Country not specified Classification basis: Source catalog labels Instruction SHA-256: f06e0003017ab87deba79dc9e96fbb8d0f867e7b3f08d06e74f6b87772e183c1