tracking-threat-actor-infrastructure

name	tracking-threat-actor-infrastructure
description	Discovers and maps adversary-controlled infrastructure (C2 servers, phishing domains, exploit-kit hosts, bulletproof hosting) by pivoting across passive DNS, certificate transparency logs, Shodan/Censys scans, WHOIS records, and network fingerprints (JARM/JA3S). Use when tracking threat actor infrastructure, expanding a known IOC into related assets, or producing STIX-based threat intelligence during a CTI investigation.
domain	cybersecurity
subdomain	threat-intelligence
tags	["threat-intelligence","cti","ioc","mitre-attack","stix","infrastructure-tracking","shodan","censys","passive-dns"]
version	1.0
author	mahipal
license	Apache-2.0
nist_csf	["ID.RA-01","ID.RA-05","DE.CM-01","DE.AE-02"]
mitre_attack	["T1591","T1592","T1593","T1589","T1566"]
mitre_f3	{"version":"1.1","tactics":["reconnaissance","resource-development"],"techniques":[{"id":"T1593","name":"Search Open Websites/Domains","tactic":"reconnaissance","source":"attack"},{"id":"T1583.001","name":"Acquire Infrastructure: Domains","tactic":"resource-development","source":"attack"},{"id":"T1583.008","name":"Acquire Infrastructure: Malvertising","tactic":"resource-development","source":"attack"},{"id":"T1583.003","name":"Acquire Infrastructure: Virtual Private Network or Server","tactic":"resource-development","source":"attack"},{"id":"F1020.002","name":"Create Fake Materials: Fake Website","tactic":"resource-development","source":"f3"},{"id":"T1608.006","name":"Stage Capabilities: SEO Poisoning","tactic":"resource-development","source":"attack"}]}

Tracking Threat Actor Infrastructure

Overview

Threat actor infrastructure tracking involves monitoring and mapping adversary-controlled assets including command-and-control (C2) servers, phishing domains, exploit kit hosts, bulletproof hosting, and staging servers. This skill covers using passive DNS, certificate transparency logs, Shodan/Censys scanning, WHOIS analysis, and network fingerprinting to discover, track, and pivot across threat actor infrastructure over time.

When to Use

• When managing security operations that require tracking threat actor infrastructure
• When improving security program maturity and operational processes
• When establishing standardized procedures for security team workflows
• When integrating threat intelligence or vulnerability data into operations

Prerequisites

• Python 3.9+ with shodan, censys, requests, stix2 libraries
• API keys: Shodan, Censys, VirusTotal, SecurityTrails, PassiveTotal
• Understanding of DNS, TLS/SSL certificates, IP allocation, ASN structure
• Familiarity with passive DNS and certificate transparency concepts
• Access to domain registration (WHOIS) lookup services

Key Concepts

Infrastructure Pivoting

Pivoting is the technique of using one known indicator to discover related infrastructure. Starting from a known C2 IP address, analysts can pivot via: passive DNS (find domains), reverse WHOIS (find related registrations), SSL certificates (find shared certs), SSH key fingerprints, HTTP response fingerprints, JARM/JA3S hashes, and WHOIS registrant data.

Passive DNS

Passive DNS databases record DNS query/response data observed at recursive resolvers. This allows analysts to find historical domain-to-IP mappings, discover domains hosted on a known C2 IP, and identify fast-flux or domain generation algorithm (DGA) behavior.

Certificate Transparency

Certificate Transparency (CT) logs publicly record all SSL/TLS certificates issued by CAs. Monitoring CT logs reveals new certificates registered for suspicious domains, helping identify phishing sites and C2 infrastructure before they become active.

Network Fingerprinting

• JARM: Active TLS server fingerprint (hash of TLS handshake responses)
• JA3S: Passive TLS server fingerprint (hash of Server Hello)
• HTTP Headers: Server banners, custom headers, response patterns
• Favicon Hash: Hash of HTTP favicon for server identification

Workflow