Identify ransomware-related network indicators, including C2 beaconing patterns, TOR exit node connections, data exfiltration flows, and encryption key exchange, by analyzing Zeek conn.log and NetFlow data. Use when threat hunting for active ransomware network activity or investigating suspected pre-encryption exfiltration during incident response.
Start a fresh conversation. Replace the highlighted placeholders.
Use analyzing-ransomware-network-indicators to analyzing-ransomware-network-indicators to analyze [Zeek conn.log or NetFlow export, plus any approved TOR/C2 intelligence] and produce a JSON incident report covering beaconing, TOR connections, likely exfiltration, composite risk, timeline, and MITRE mapping.
Required inputs
[Zeek conn.log or NetFlow export, plus any approved TOR/C2 intelligence]
User-approved starter prompt based on a pinned source version; check current skill requirements before running. Task evidence ↗
SKILL.md
name: analyzing-ransomware-network-indicatorsdescription: Identify ransomware-related network indicators, including C2 beaconing patterns, TOR exit node connections, data exfiltration flows, and encryption key exchange, by analyzing Zeek conn.log and NetFlow data. Use when threat hunting for active ransomware network activity or investigating suspected pre-encryption exfiltration during incident response.domain: cybersecuritysubdomain: threat-huntingtags: - ransomware- c2-beaconing- zeek- netflow- tor- exfiltration- network-forensicsversion: '1.0'author: mahipallicense: Apache-2.0d3fend_techniques: - File Metadata Consistency Validation- Certificate Analysis- Application Protocol Command Analysis- Content Format Conversion- File Content Analysisnist_csf: - DE.CM-01- DE.AE-02- DE.AE-07- ID.RA-05mitre_attack: - T1071.001- T1573- T1048- T1567.002- T1486mitre_f3: version: '1.1' tactics: - positioning - monetization techniques: - id: T1219 name: Remote Access Tools tactic: positioning source: attack - id: F1018 name: Convert to Cryptocurrency tactic: monetization source: f3 - id: F1047 name: Transfer of funds tactic: monetization source: f3
Analyzing Ransomware Network Indicators
Overview
Before and during ransomware execution, adversaries establish C2 channels, exfiltrate data, and download encryption keys. This skill analyzes Zeek conn.log and NetFlow data to detect beaconing patterns (regular-interval callbacks), connections to known TOR exit nodes, large outbound data transfers, and suspicious DNS activity associated with ransomware families.
When to Use
When investigating security incidents that require analyzing ransomware network indicators
When building detection rules or threat hunting queries for this domain
When SOC analysts need structured procedures for this analysis type
When validating security monitoring coverage for related attack techniques
Prerequisites
Zeek conn.log files or NetFlow CSV/JSON exports
Python 3.8+ with standard library
TOR exit node list (fetched from Tor Project or threat intel feeds)
Optional: Known ransomware C2 IOC list
Steps
Parse Connection Logs — Ingest Zeek conn.log (TSV) or NetFlow records into structured format
Detect Beaconing Patterns — Calculate connection interval statistics (mean, stddev, coefficient of variation) to identify periodic callbacks
Check TOR Exit Node Connections — Cross-reference destination IPs against current TOR exit node list
Identify Data Exfiltration — Flag connections with unusually high outbound byte ratios to external IPs
Analyze DNS Patterns — Detect DGA-like domain queries and high-entropy subdomains
Score and Correlate — Apply composite risk scoring across all indicator types
Generate Report — Produce structured report with timeline and MITRE ATT&CK mapping
Expected Output
JSON report with beaconing detections and interval statistics
TOR exit node connection alerts
Data exfiltration flow analysis
Composite ransomware risk score with MITRE mapping (T1071, T1573, T1041)