detecting-service-account-abuse

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

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.
4. Analyze Results: Examine query results for anomalies, correlating across multiple data sources.
5. Validate Findings: Distinguish true positives from false positives through contextual analysis.
6. Correlate Activity: Link findings to broader attack chains and threat actor TTPs.
7. 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

1. Scenario 1: Service account RDP to domain controller
2. Scenario 2: SQL service accessing file shares outside scope
3. Scenario 3: Backup service lateral movement off-hours
4. Scenario 4: Compromised svc with DA privileges used for DCSync

Output Format

Hunt ID: TH-DETECT-[DATE]-[SEQ]
Technique: T1078.002
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]