# Analyzing Network Covert Channels In Malware

Detect and analyze covert communication channels used by malware including DNS...

- Repository: https://github.com/AgentFlocks/flocks (504 stars)
- Category: Security
- License: Apache-2.0
- Last updated: 2026-10-30
- Runs scripts: yes, review before use

## Install

Claude Code: `npx skills add AgentFlocks/flocks --skill analyzing-network-covert-channels-in-malware -g -a claude-code -y`
Codex: `npx skills add AgentFlocks/flocks --skill analyzing-network-covert-channels-in-malware -g -a codex -y`
Cursor: `npx skills add AgentFlocks/flocks --skill analyzing-network-covert-channels-in-malware -g -a cursor -y`
Gemini CLI: `npx skills add AgentFlocks/flocks --skill analyzing-network-covert-channels-in-malware -g -a gemini-cli -y`

## Description

Detect and analyze covert communication channels used by malware including DNS tunneling, ICMP exfiltration, steganographic HTTP, and protocol abuse for C2 and data exfiltration.

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

# Analyzing Network Covert Channels in Malware

## Overview

Malware uses covert channels to disguise C2 communication and data exfiltration within legitimate-looking network traffic. DNS tunneling encodes data in DNS queries and responses (used by tools like iodine, dnscat2, and malware families like FrameworkPOS). ICMP tunneling hides data in echo request/reply payloads (icmpsh, ptunnel). HTTP covert channels embed C2 data in headers, cookies, or steganographic images. Protocol abuse exploits allowed protocols to bypass firewalls. DNS tunneling detection achieves 99%+ recall with modern ML-based approaches, though low-throughput exfiltration remains challenging. Palo Alto Unit42 tracked three major DNS tunneling campaigns (TrkCdn, SecShow, Savvy Seahorse) through 2024, showing the technique's continued prevalence.


## When to Use

- When investigating security incidents that require analyzing network covert channels in malware
- 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

- Python 3.9+ with `scapy`, `dpkt`, `dnslib`
- Wireshark/tshark for PCAP analysis
- Zeek (formerly Bro) for network monitoring
- DNS query logging infrastructure
- Understanding of DNS, ICMP, HTTP protocols at packet level

## Workflow

### Step 1: DNS Tunneling Detection

```python
#!/usr/bin/env python3
"""Detect DNS tunneling and covert channels in network traffic."""
import sys
import json
import math
from collections import Counter, defaultdict

try:
    from scapy.all import rdpcap, DNS, DNSQR, DNSRR, IP, ICMP
except ImportError:
    print("pip install scapy")
    sys.exit(1)


def entropy(data):
    if not data:
        return 0
    freq = Counter(data)
    length = len(data)
    return -sum((c/length) * math.log2(c/length) for c in freq.values())

The rest: https://github.com/AgentFlocks/flocks/blob/HEAD/.flocks/flockshub/plugins/skills/Anthropic-Cybersecurity-Skills/analyzing-network-covert-channels-in-malware/SKILL.md