detecting-insider-threat-behaviors

name	detecting-insider-threat-behaviors
description	Detect insider threat behavioral indicators including unusual data access, off-hours activity, mass file downloads, privilege abuse, and resignation-correlated data theft.
domain	cybersecurity
subdomain	threat-hunting
tags	["threat-hunting","mitre-attack","insider-threat","data-theft","ueba","proactive-detection"]
version	1.0
author	mahipal
license	Apache-2.0
d3fend_techniques	["Restore Access","Password Authentication","Biometric Authentication","Strong Password Policy","Restore User Account Access"]
nist_csf	["DE.CM-01","DE.AE-02","DE.AE-07","ID.RA-05"]

Detecting Insider Threat Behaviors

When to Use

• When proactively hunting for indicators of detecting insider threat behaviors in the environment
• After threat intelligence indicates active campaigns using these techniques
• During incident response to scope compromise related to these techniques
• When EDR or SIEM alerts trigger on related indicators
• During periodic security assessments and purple team exercises

Detection Gaps & Validation

• Network logs alone miss the highest-signal exfil. SIEM-only hunting overlooks USB mass copy (Security 6416 PnP device, Microsoft-Windows-DriverFrameworks-UserMode 2003/2102), local printing, and photographing the screen. Add removable-media and DLP telemetry.
• Personal-cloud exfil blends with sanctioned use. Uploads to personal OneDrive/Gmail/Dropbox look like normal SaaS traffic on raw byte volume. You need a CASB/proxy with per-user behavioral baselines, not a global threshold.
• Low-and-slow staging under daily limits evades volume rules — aggregate reads per user over weeks and correlate with HR signals (resignation notice, PIP, role change).
• Off-hours must be per-user. A single org-wide "after 6pm" rule drowns shift workers and global teams in false positives; use individual UEBA baselines instead.
• Privileged abuse looks authorized: admins reading HR/finance shares are "in their rights." Monitor 4663 object-access on sensitive shares (with SACLs in place) and 4662 on AD objects to spot scope creep.
• Validate the rule fires: as a test account, copy a large benign file set to USB and to a personal cloud account, and confirm 4663/6416 and the DLP/CASB event are generated and alert.
• Tune false positives: backups, OneDrive/Box sync clients, and CI/dev builds generate bulk reads. Allowlist service accounts and known sync processes before alerting.

Prerequisites

• EDR platform with process and network telemetry (CrowdStrike, MDE, SentinelOne)
• SIEM with relevant log data ingested (Splunk, Elastic, Sentinel)
• Sysmon deployed with comprehensive configuration
• Windows Security Event Log forwarding enabled
• Threat intelligence feeds for IOC correlation

Workflow

1. Formulate Hypothesis: Define a testable hypothesis based on threat intelligence or ATT&CK gap analysis.
2. Identify Data Sources: Determine which logs and telemetry are needed to validate or refute the hypothesis.
3. Execute Queries: Run detection queries against SIEM and EDR platforms to collect relevant events.