# Analyzing Indicators Of Compromise

Analyzes indicators of compromise (IOCs) including IP addresses, domains, file hashes...

- Repository: https://github.com/mukul975/Anthropic-Cybersecurity-Skills (35398 stars)
- Category: Security
- License: Apache-2.0
- Last updated: 2026-08-31
- Runs scripts: yes, review before use

## Install

Claude Code: `npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill analyzing-indicators-of-compromise -g -a claude-code -y`
Codex: `npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill analyzing-indicators-of-compromise -g -a codex -y`
Cursor: `npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill analyzing-indicators-of-compromise -g -a cursor -y`
Gemini CLI: `npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill analyzing-indicators-of-compromise -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add mukul975/Anthropic-Cybersecurity-Skills`

## Description

Analyzes indicators of compromise (IOCs) including IP addresses, domains, file hashes, URLs, and email artifacts to determine maliciousness confidence, campaign attribution, and blocking priority. Use when triaging IOCs from phishing emails, security alerts, or external threat feeds; enriching raw IOCs with multi-source intelligence; or making block/monitor/whitelist decisions. Activates for requests involving VirusTotal, AbuseIPDB, MalwareBazaar, MISP, or IOC enrichment pipelines.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Analyzing Indicators of Compromise

## When to Use

Use this skill when:
- A phishing email or alert generates IOCs (URLs, IP addresses, file hashes) requiring rapid triage
- Automated feeds deliver bulk IOCs that need confidence scoring before ingestion into blocking controls
- An incident investigation requires contextual enrichment of observed network artifacts

**Do not use** this skill in isolation for high-stakes blocking decisions, always combine automated enrichment with analyst judgment, especially for shared infrastructure (CDNs, cloud providers).

## Prerequisites

- VirusTotal API key (free or Enterprise) for multi-AV and sandbox lookup
- AbuseIPDB API key for IP reputation checks
- MISP instance or TIP for cross-referencing against known campaigns
- Python with `requests` and `vt-py` libraries, or SOAR platform with pre-built connectors

## Workflow

### Step 1: Normalize and Classify IOC Types

Before enriching, classify each IOC:
- **IPv4/IPv6 address**: Check if RFC 1918 private (skip external enrichment), validate format
- **Domain/FQDN**: Defang for safe handling (`evil[.]com`), extract registered domain via tldextract
- **URL**: Extract domain + path separately; check for redirectors
- **File hash**: Identify hash type (MD5/SHA-1/SHA-256); prefer SHA-256 for uniqueness
- **Email address**: Split into domain (check MX/DMARC) and local part for pattern analysis

Defang IOCs in documentation (replace `.` with `[.]` and `://` with `[://]`) to prevent accidental clicks.

### Step 2: Multi-Source Enrichment

**VirusTotal (file hash, URL, IP, domain)**:
```python
import vt

client = vt.Client("YOUR_VT_API_KEY")

# File hash lookup
file_obj = client.get_object(f"/files/{sha256_hash}")
detections = file_obj.last_analysis_stats
print(f"Malicious: {detections['malicious']}/{sum(detections.values())}")

The rest: https://github.com/mukul975/Anthropic-Cybersecurity-Skills/blob/HEAD/skills/analyzing-indicators-of-compromise/SKILL.md