Detecting Insider Threat Behaviors
FreeProactively identify insider threats with behavioral detection.
Free · Opens the source repo
What Detecting Insider Threat Behaviors does
Detecting Insider Threat Behaviors is a skill designed for security professionals looking to proactively hunt for indicators of insider threats within their organization. This skill enables users to identify unusual behaviors such as off-hours data access, mass file downloads, privilege abuse, and potential data theft correlated with employee resignations. By leveraging existing telemetry from EDR platforms and SIEM systems, this skill facilitates the detection of malicious or negligent insider activities, providing a structured approach to threat hunting and incident response.
The skill operates through a defined workflow that begins with formulating a hypothesis based on threat intelligence or ATT&CK gap analysis. Users will identify necessary data sources, execute detection queries against their SIEM or EDR platforms, and analyze the results for anomalies. This process allows for the validation of findings, distinguishing true positives from false positives through contextual analysis, and correlating activities to broader attack chains and TTPs of threat actors.
This skill is particularly useful during threat-hunting exercises, incident response scenarios, and periodic security assessments. It requires a robust security infrastructure, including an EDR platform with comprehensive telemetry, a SIEM with relevant log data, and the deployment of Sysmon for detailed Windows event monitoring. By utilizing this skill, organizations can enhance their security posture and respond effectively to potential insider threats before they escalate into significant incidents.
Security teams can benefit from the structured output format provided by the skill, which includes a unique Hunt ID, the technique used, host and user context, evidence gathered, risk level, confidence in the findings, and recommended actions. This structured reporting aids in documentation and facilitates communication within security teams and with stakeholders.
When to use it
Use this skill when actively hunting for insider threat indicators or during incident response to assess potential compromises.
When not to use it
This skill may not be suitable for environments lacking the required EDR and SIEM infrastructure or where insider threats are not a concern.
What you can build with it
Bulk file downloads before resignation
Detect unusual bulk file downloads by employees prior to their resignation, indicating potential data theft.
Unauthorized access by IT admin
Identify instances where IT administrators access sensitive HR data outside of their job responsibilities.
Service account misuse
Monitor for unauthorized data queries executed by service accounts, which may signal insider threats.
How to install Detecting Insider Threat Behaviors
View source1. Install with the skills CLI
npx skills add mukul975/anthropic-cybersecurity-skills/detecting-insider-threat-behaviors --agent claude-code2. Or install it manually
Download the skill folder and drop it into ~/.claude/skills/ for all projects, or .claude/skills/ to scope it to one repo. Restart Claude Code so it picks up the new skill.
Anthropic's agentic coding CLI, and the reference implementation of Agent Skills. Drop a skill folder into ~/.claude/skills and Claude Code loads it automatically whenever a task matches the skill's description. Claude Code docs
Inside SKILL.md
Written by mukul975Detecting 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
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
- Formulate Hypothesis: Define a testable hypothesis based on threat intelligence or ATT&CK gap analysis.
- Identify Data Sources: Determine which logs and telemetry are needed to validate or refute the hypothesis.
- Execute Queries: Run detection queries against SIEM and EDR platforms to collect relevant events.
- Analyze Results: Examine query results for anomalies, correlating across multiple data sources.
- Validate Findings: Distinguish true positives from false positives through contextual analysis.
- Correlate Activity: Link findings to broader attack chains and threat actor TTPs.
- Document and Report: Record findings, update detection rules, and recommend response actions.
Key Concepts
| Concept | Description |
|---|---|
| T1078 | Valid Accounts |
| T1530 | Data from Cloud Storage Object |
| T1567 | Exfiltration Over Web Service |
Tools & Systems
| Tool | Purpose |
|---|---|
| CrowdStrike Falcon | EDR telemetry and threat detection |
| Microsoft Defender for Endpoint | Advanced hunting with KQL |
| Splunk Enterprise | SIEM log analysis with SPL queries |
| Elastic Security | Detection rules and investigation timeline |
| Sysmon | Detailed Windows event monitoring |
| Velociraptor | Endpoint artifact collection and hunting |
| Sigma Rules | Cross-platform detection rule format |
Common Scenarios
- Scenario 1: Employee downloading bulk files before resignation
- Scenario 2: IT admin accessing HR data outside job function
- Scenario 3: Service account used for unauthorized data queries
- Scenario 4: Contractor copying source code to personal cloud storage
Output Format
Hunt ID: TH-DETECT-[DATE]-[SEQ]
Technique: T1078
Host: [Hostname]
User: [Account context]
Evidence: [Log entries, process trees, network data]
Risk Level: [Critical/High/Medium/Low]
Confidence: [High/Medium/Low]
Recommended Action: [Containment, investigation, monitoring]
Frequently asked questions about Detecting Insider Threat Behaviors
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