Files
Anthropic-Cybersecurity-Skills/skills/analyzing-ransomware-network-indicators/SKILL.md
T
mukul975 efca3ec611 feat: add NIST CSF 2.0 nist_csf field to all 754 cybersecurity skills
Mapped every skill to NIST CSF 2.0 subcategory IDs (GV/ID/PR/DE/RS/RC functions)
based on subdomain and content analysis. Restores 11 skills corrupted during
prior rebase, re-enriching with ATLAS, D3FEND, NIST AI RMF, and CSF 2.0 fields.

All 754 skills now carry structured mappings for all 5 security frameworks:
- MITRE ATT&CK (in tags)
- MITRE ATLAS v5.5 (atlas_techniques)
- MITRE D3FEND v1.3 (d3fend_techniques)
- NIST AI RMF 1.0 (nist_ai_rmf)
- NIST CSF 2.0 (nist_csf)
2026-04-06 11:17:40 +02:00

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Markdown

---
name: analyzing-ransomware-network-indicators
description: Identify ransomware network indicators including C2 beaconing patterns, TOR exit node connections, data exfiltration
flows, and encryption key exchange via Zeek conn.log and NetFlow analysis
domain: cybersecurity
subdomain: threat-hunting
tags:
- ransomware
- c2-beaconing
- zeek
- netflow
- tor
- exfiltration
- network-forensics
version: '1.0'
author: mahipal
license: Apache-2.0
d3fend_techniques:
- File Metadata Consistency Validation
- Certificate Analysis
- Application Protocol Command Analysis
- Content Format Conversion
- File Content Analysis
nist_csf:
- DE.CM-01
- DE.AE-02
- DE.AE-07
- ID.RA-05
---
# 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
1. **Parse Connection Logs** — Ingest Zeek conn.log (TSV) or NetFlow records into structured format
2. **Detect Beaconing Patterns** — Calculate connection interval statistics (mean, stddev, coefficient of variation) to identify periodic callbacks
3. **Check TOR Exit Node Connections** — Cross-reference destination IPs against current TOR exit node list
4. **Identify Data Exfiltration** — Flag connections with unusually high outbound byte ratios to external IPs
5. **Analyze DNS Patterns** — Detect DGA-like domain queries and high-entropy subdomains
6. **Score and Correlate** — Apply composite risk scoring across all indicator types
7. **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)