Skill

hunting-for-cobalt-strike-beacons

From asi

Detects Cobalt Strike beacon C2 activity in network traffic using Zeek logs, Suricata rules, Python PCAP analysis for TLS cert signatures, JA3/JA3S/JARM fingerprints, jitter, and HTTP profiles.

Python

security

npx claudepluginhub plurigrid/asi --plugin asi

Tool Access

This skill uses the workspace's default tool permissions.

Preview

SKILL.md

Similar Skills

hunting-for-cobalt-strike-beacons

5.9k

Detects Cobalt Strike beacons using default TLS cert serial (8BB00EE), JA3/JA3S/JARM fingerprints, HTTP C2 profiles, jitter analysis, and named pipes via Zeek, Suricata, Python PCAP. For threat hunting.

3 files

cybersecurity-skills

hunting-for-cobalt-strike-beacons

Detects Cobalt Strike beacons in network traffic via default TLS cert serial 8BB00EE, JA3/JA3S/JARM fingerprints, HTTP C2 profile matching, jitter analysis, named pipes using Zeek, Suricata, Python PCAP.

3 files

cybersecurity-skills-zh

analyzing-command-and-control-communication

Analyzes malware C2 protocols (HTTP, HTTPS, DNS, custom) for beacon patterns, command structures, encoding, and infrastructure mapping. Useful for detection signatures and threat intelligence.

asi

Stats

Parent Repo Stars16

Parent Repo Forks5

Last CommitApr 4, 2026

Actions

View Source View Plugin View on GitHub View README

Help us improve

Share bugs, ideas, or general feedback.

Hunting for Cobalt Strike Beacons

Overview

Cobalt Strike is the most prevalent command-and-control framework used by both red teams and threat actors. Beacon, its primary payload, communicates with team servers using configurable HTTP/HTTPS/DNS profiles that can mimic legitimate traffic. However, default configurations and behavioral patterns remain detectable through TLS certificate analysis (default serial 8BB00EE), JA3/JA3S fingerprinting, beacon interval jitter analysis, and HTTP malleable profile pattern matching. This skill covers building detection capabilities using Zeek network logs, Suricata IDS rules, and Python-based PCAP analysis to identify beacon callbacks in network traffic.

When to Use

When investigating security incidents that require hunting for cobalt strike beacons
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 6.0+ with JA3 and HASSH packages installed
Suricata 7.0+ with Emerging Threats ruleset
Python 3.9+ with scapy and dpkt libraries
Network traffic captures (PCAP) or live Zeek logs
RITA (Real Intelligence Threat Analytics) for beacon scoring
Threat intelligence feeds with known Cobalt Strike IOCs

Steps

Step 1: TLS Certificate Analysis

Detect default Cobalt Strike certificates using JA3S fingerprints, certificate serial numbers, and JARM fingerprints in Zeek ssl.log.

Step 2: Beacon Interval Analysis

Analyze connection timing patterns to identify regular callback intervals with configurable jitter, characteristic of beacon behavior.

Step 3: HTTP Profile Detection

Match HTTP request patterns (URI paths, headers, user-agents) against known malleable C2 profiles.

Step 4: Correlate and Score

Combine multiple indicators (TLS + timing + HTTP profile) into a composite beacon confidence score.

Expected Output

JSON report containing detected beacon candidates with confidence scores, TLS fingerprints, timing analysis, HTTP profile matches, and recommended response actions.