hunting-dns-tunneling-and-exfiltration

hunting-dns-tunneling-and-exfiltration is a skill for Claude Code, Codex from meltedinhex/analyst-ai-pack. It costs 74 tokens per session (788 once invoked), scanned A, original, Apache-2.0.

A network security hunt for DNS tunnelling, where data is hidden inside DNS queries, and DNS exfiltration, where data is carried out that way. It scores DNS logs for unusual names, volume, encoding, and record types.

In plain words
What is it for?
It helps rank domains with many unique or encoded subdomains, unusually long or high-entropy labels, high query rates, and unusual TXT, NULL, or CNAME usage.
Why use it?
DNS is allowed in most networks, so malicious data can sometimes blend into ordinary lookups. Combining several signals is more useful than treating long domain names alone as proof.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit It helps rank domains with many unique or encoded subdomains, unusually long or high-entropy labels, high query rates, and unusual TXT, NULL, or CNAME usage.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/meltedinhex/analyst-ai-pack/hunting-dns-tunneling-and-exfiltration
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add meltedinhex/analyst-ai-pack --skill hunting-dns-tunneling-and-exfiltration
Clone the repo
git clone --depth 1 https://github.com/meltedinhex/analyst-ai-pack

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for hunting-dns-tunneling-and-exfiltration

README.md
[![agentmods](https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/hunting-dns-tunneling-and-exfiltration/github.svg)](https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/hunting-dns-tunneling-and-exfiltration)
Your own site
<a href="https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/hunting-dns-tunneling-and-exfiltration"><img src="https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/hunting-dns-tunneling-and-exfiltration/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for hunting-dns-tunneling-and-exfiltration

Your own site · 80×15
<a href="https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/hunting-dns-tunneling-and-exfiltration"><img src="https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/hunting-dns-tunneling-and-exfiltration.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 74 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 788 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00074 $0.00788
Opus 5 $0.00037 $0.00394
Sonnet 5 $0.00015 $0.00158
Haiku 4.5 $0.00007 $0.00079

Measured 9d ago against content hash c23d70afef04, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

hunting-dns-tunneling-and-exfiltration scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/analyst.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/hunting-dns-tunneling-and-exfiltration/SKILL.md · 95 lines

How it starts

The opening of the file, as written. The whole thing — 95 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Hunting DNS Tunneling and Exfiltration

When to Use

  • You have DNS query logs (resolver, Zeek dns.log, Windows DNS) and want to find tunneling or exfiltration over DNS.
  • You are testing a hypothesis that an implant uses DNS as a covert channel.
  • You need to rank domains by tunneling indicators across many queries.

Do not use query length alone as a verdict — CDNs, antivirus lookups, and some SaaS use long encoded labels legitimately; combine entropy, volume, and record-type signals.

Prerequisites

  • DNS logs with query name, query type, source, and timestamp, over a meaningful window.
  • A way to whitelist known-benign high-volume domains (security vendors, CDNs).

Workflow

Step 1: Aggregate by registered domain

Group queries under their registered/parent domain so per-domain volume and subdomain diversity are visible.

Step 2: Score tunneling indicators

Weight: high unique-subdomain count, long average label length, high subdomain entropy (encoded data), heavy TXT/NULL/CNAME usage, and high query rate to one domain.

python scripts/analyst.py hunt dns.json

Step 3: Estimate exfiltration volume

Sum encoded bytes implied by query lengths per domain; sustained high volume to a single nameserver suggests data egress.

Step 4: Whitelist and pivot

Remove known-benign high-entropy domains; for survivors, check domain age/registration, the authoritative nameserver, and the originating host.

Step 5: Confirm and respond

Validate by decoding sampled labels where possible and correlating with host activity; escalate confirmed tunnels and write a detection.

Validation

  • High-score domains combine multiple signals (entropy + volume + record type), not one alone.
  • Benign high-volume domains are whitelisted, keeping the list reviewable.
  • Confirmed tunnels tie to a specific host and a young/suspicious domain.

Pitfalls

  • Flagging long labels from CDNs and AV telemetry as tunneling.
  • Aggregating by full FQDN instead of registered domain, hiding subdomain diversity.
  • Ignoring record type; TXT/NULL carry far more data than A records.

Read the full file on GitHub · 95 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 9d ago First seen · 95 lines · 74 tokens per session scan A c23d70afef04

Subscribe to this mod's changes

hunting-dns-tunneling-and-exfiltration is a skill published in the GitHub repository meltedinhex/analyst-ai-pack (22 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 74 tokens to every session and 788 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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