Detect abuse of service accounts by hunting for anomalous interactive logons, privilege escalation, and lateral movement using EDR/SIEM telemetry (CrowdStrike Falcon, Microsoft Defender, Splunk, Elastic Security, Sysmon, Velociraptor) and Sigma detection rules. Use when hunting for service-account misuse or investigating a service account performing unexpected interactive logons.
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Use detecting-service-account-abuse to investigate [service account or alert] using available [SIEM/EDR telemetry], producing detection queries, validated findings, correlated activity, and recommended response actions.
Required inputs
[service account or alert]
[SIEM/EDR telemetry]
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SKILL.md
name: detecting-service-account-abusedescription: Detect abuse of service accounts by hunting for anomalous interactive logons, privilege escalation, and lateral movement using EDR/SIEM telemetry (CrowdStrike Falcon, Microsoft Defender, Splunk, Elastic Security, Sysmon, Velociraptor) and Sigma detection rules. Use when hunting for service-account misuse or investigating a service account performing unexpected interactive logons.domain: cybersecuritysubdomain: threat-huntingtags: - threat-hunting- mitre-attack- service-accounts- privilege-escalation- t1078- proactive-detectionversion: '1.0'author: mahipallicense: Apache-2.0d3fend_techniques: - Restore Access- Password Authentication- Biometric Authentication- Strong Password Policy- Restore User Account Accessnist_csf: - DE.CM-01- DE.AE-02- DE.AE-07- ID.RA-05mitre_attack: - T1078.002- T1021.001- T1098.001- T1550.002
Detecting Service Account Abuse
When to Use
When proactively hunting for indicators of detecting service account abuse 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
T1078.002
Domain Accounts
T1078.001
Default Accounts
T1021
Remote Services
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: Service account RDP to domain controller
Scenario 2: SQL service accessing file shares outside scope
Scenario 3: Backup service lateral movement off-hours
Scenario 4: Compromised svc with DA privileges used for DCSync