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Mahipal
2fb6a9faff
Each rewritten description now states both what the skill does (concrete capability, named tools/artifacts) and an explicit when-to-use trigger, improving agent discovery/activation. Grounded in each skill's own body; changes confined to the `description` field only (bodies and all other frontmatter untouched). Produced by a gated audit->rewrite->recheck loop (548 -> 0 flagged) with a sampled anti-invention check (0 ungrounded). Schema: 817/817 pass. Framework-ID gate: 0 defects.
102 lines
3.6 KiB
Markdown
102 lines
3.6 KiB
Markdown
---
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name: hunting-for-unusual-network-connections
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description: Runs a hypothesis-driven threat hunt for command-and-control activity (T1071) by querying SIEM/EDR network telemetry for anomalous outbound traffic, rare destinations, non-standard ports, and unusual connection frequencies from endpoints. Use when hunting for beaconing/C2 traffic, after threat intel flags suspicious infrastructure, or when alerts fire on anomalous connections.
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domain: cybersecurity
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subdomain: threat-hunting
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tags:
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- threat-hunting
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- mitre-attack
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- network-analysis
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- c2
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- anomaly-detection
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- proactive-detection
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version: '1.0'
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author: mahipal
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license: Apache-2.0
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d3fend_techniques:
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- File Metadata Consistency Validation
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- Certificate Analysis
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- Application Protocol Command Analysis
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- Content Format Conversion
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- File Content Analysis
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nist_csf:
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- DE.CM-01
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- DE.AE-02
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- DE.AE-07
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- ID.RA-05
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mitre_attack:
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- T1046
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- T1057
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- T1082
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- T1083
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- T1071
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---
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# Hunting For Unusual Network Connections
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## When to Use
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- When proactively hunting for indicators of hunting for unusual network connections in the environment
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- After threat intelligence indicates active campaigns using these techniques
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- During incident response to scope compromise related to these techniques
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- When EDR or SIEM alerts trigger on related indicators
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- During periodic security assessments and purple team exercises
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## Prerequisites
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- EDR platform with process and network telemetry (CrowdStrike, MDE, SentinelOne)
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- SIEM with relevant log data ingested (Splunk, Elastic, Sentinel)
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- Sysmon deployed with comprehensive configuration
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- Windows Security Event Log forwarding enabled
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- Threat intelligence feeds for IOC correlation
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## Workflow
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1. **Formulate Hypothesis**: Define a testable hypothesis based on threat intelligence or ATT&CK gap analysis.
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2. **Identify Data Sources**: Determine which logs and telemetry are needed to validate or refute the hypothesis.
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3. **Execute Queries**: Run detection queries against SIEM and EDR platforms to collect relevant events.
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4. **Analyze Results**: Examine query results for anomalies, correlating across multiple data sources.
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5. **Validate Findings**: Distinguish true positives from false positives through contextual analysis.
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6. **Correlate Activity**: Link findings to broader attack chains and threat actor TTPs.
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7. **Document and Report**: Record findings, update detection rules, and recommend response actions.
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## Key Concepts
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| Concept | Description |
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|---------|-------------|
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| T1071 | Application Layer Protocol |
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| T1095 | Non-Application Layer Protocol |
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| T1571 | Non-Standard Port |
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## Tools & Systems
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| Tool | Purpose |
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|------|---------|
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| CrowdStrike Falcon | EDR telemetry and threat detection |
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| Microsoft Defender for Endpoint | Advanced hunting with KQL |
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| Splunk Enterprise | SIEM log analysis with SPL queries |
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| Elastic Security | Detection rules and investigation timeline |
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| Sysmon | Detailed Windows event monitoring |
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| Velociraptor | Endpoint artifact collection and hunting |
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| Sigma Rules | Cross-platform detection rule format |
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## Common Scenarios
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1. **Scenario 1**: Backdoor communicating to C2 on non-standard port
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2. **Scenario 2**: Data exfiltration over DNS to attacker nameserver
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3. **Scenario 3**: Compromised host scanning internal network
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4. **Scenario 4**: Cryptominer connecting to mining pool
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## Output Format
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```
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Hunt ID: TH-HUNTIN-[DATE]-[SEQ]
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Technique: T1071
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Host: [Hostname]
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User: [Account context]
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Evidence: [Log entries, process trees, network data]
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Risk Level: [Critical/High/Medium/Low]
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Confidence: [High/Medium/Low]
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Recommended Action: [Containment, investigation, monitoring]
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```
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