nmap

A guide for using Nmap, a tool that checks computers and networks for open connection points and the services running on them.

In plain words
What is it for?
Use it to run quick, full, UDP, stealth, and service-detection scans, run Nmap scripts, and save results in several formats.
Why use it?
It provides an organised way to discover network services, identify their versions, and check for possible weaknesses.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/brownfinesecurity/iothackbot/nmap
Any agent
npx skills add BrownFineSecurity/iothackbot --skill nmap
Clone the repo
git clone --depth 1 https://github.com/BrownFineSecurity/iothackbot

Made for: Claude Code, Codex.

Per session 53 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,314 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. Scan, not verified.
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 $0.00053 $0.04314
Opus 5 $0.00026 $0.02157
Sonnet 5 $0.00011 $0.00863
Haiku 4.5 $0.00005 $0.00431

Measured 2d ago against content hash 12e31fa7e928, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

nmap scanned grade B with 1 finding 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 2d ago.

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.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

sudo nmap -p- <target> -oA <output-dir>/nmap-portscan
skills/nmap/SKILL.md · 533 lines

How it starts

The opening of the file, as written. The whole thing — 533 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Nmap Scan - Professional Network Reconnaissance

You are helping the user perform professional network reconnaissance and port scanning using nmap. This skill provides guidance for various scan types, output formats, and result analysis.

Output Directory

Directory Structure

nmap-output/
├── nmap-portscan.nmap      # Initial fast port discovery
├── nmap-portscan.xml
├── nmap-portscan.gnmap
├── nmap-services.nmap      # Detailed service detection on open ports
├── nmap-services.xml
└── nmap-services.gnmap

IMPORTANT: Always save nmap output to an organized directory structure. By default, use ./nmap-output/ or specify a custom directory.

Default Scanning Strategy

IMPORTANT: Unless the user explicitly requests a different scan type, ALWAYS use this two-phase approach:

Phase 1: Fast Port Discovery (Root SYN Scan)

sudo nmap -p- <target> -oA <output-dir>/nmap-portscan
  • Why sudo: Running as root enables fast SYN scan (-sS is implicit)
  • Why -p-: Scans all 65535 ports quickly
  • Duration: Typically 1-3 minutes for SYN scan
  • Output: List of all open ports

Host Down Detection: If the scan output contains "Note: Host seems down", automatically retry with:

sudo nmap -p- -Pn <target> -oA <output-dir>/nmap-portscan
  • -Pn: Skip host discovery, treat host as online
  • Use this when firewalls block ping probes

Phase 2: Targeted Service Detection

After Phase 1 completes, parse the open ports and run:

nmap -p <OPEN_PORT_LIST> -sV -sC <target> -oA <output-dir>/nmap-services
  • -p <OPEN_PORT_LIST>: Only scan the ports found to be open (e.g., -p 23,80,443,554,8000)
  • -sV: Service version detection
  • -sC: Run default NSE scripts for additional enumeration
  • Duration: Usually 1-3 minutes since only scanning known open ports

Why This Strategy?

  1. Speed: Fast SYN scan finds all open ports in 1-3 minutes
  2. Thoroughness: Covers all 65535 ports, not just top 1000
  3. Efficiency: Service detection only runs on confirmed open ports
  4. Accuracy: Two-phase approach reduces false negatives

Read the full file on GitHub · 533 lines

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. 2d ago First seen · 533 lines · 53 tokens per session scan B 12e31fa7e928

Subscribe to this mod's changes

nmap is a skill published in the GitHub repository BrownFineSecurity/iothackbot (819 stars, last pushed 3mo ago), licensed MIT. It adds 53 tokens to every session and 4,314 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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