Network Scanner

Network Scanner (Nmap)

Authorized network reconnaissance and attack-surface mapping with Nmap. Discovers live hosts, open ports, services, versions, and OS fingerprints, then produces a defensive findings report.

Language rule: All skill instructions use English. Final summary presented to the user must be in Vietnamese.

0. Authorization & Routing

Operates under MASTER_POLICY.md §1-§2.

Scope gate — required before any scan. Only scan hosts/ranges the user owns or is explicitly authorized to assess (written engagement, bug-bounty scope, internal assignment, lab/CTF, or their own network). If scope is unclear, ask one concise question before scanning. Do not scan third-party or public infrastructure without stated authorization.

This skill performs read-only reconnaissance. It does not exploit, brute-force, DoS, or run intrusive NSE categories (dos, exploit, brute, intrusive) unless the user explicitly requests them and confirms authorization.

Prerequisites (Windows)

1. Install Nmap for Windows (bundles Npcap, required for raw packet scans):
   • Recommended: download the latest installer from https://nmap.org/download.html and run it as Administrator (the Npcap driver needs elevation).
   • Avoid winget install Insecure.Nmap for now — its manifest points at a stale 7.80 URL and fails with a download-size error.
   • Without Npcap, Nmap still works via TCP connect scan (-sT); you lose SYN scan and OS detection.
2. Default install path: C:\Program Files (x86)\Nmap\nmap.exe. The wrapper auto-detects PATH and this path.
3. Run PowerShell as Administrator for -sS (SYN scan), OS detection (-O), and raw-packet host discovery. Without admin, Nmap falls back to TCP connect scan (-sT), which still works.
4. Python 3 for the parser (only Python stdlib is used — no extra install).

Verify:

python network-scanner\scripts\nmap_scan.py --check

Step 1 — Host Discovery (find live hosts)

Ping-sweep a subnet to see what is up (no port scan):

python network-scanner\scripts\nmap_scan.py 192.168.1.0/24 --profile discovery --out output\nmap

python network-scanner/scripts/nmap_scan.py 192.168.1.0/24 --profile discovery --out output/nmap

Step 2 — Port & Service Scan

Scan a host for open ports with service/version detection (default profile):

python network-scanner\scripts\nmap_scan.py 192.168.1.10 --profile service --out output\nmap

Profiles:

Pass extra raw Nmap flags after --:

python network-scanner\scripts\nmap_scan.py 192.168.1.10 --profile service --out output\nmap -- -p 22,80,443,3389

Step 3 — Parse into Findings Report

Every run writes raw Nmap output (.xml, .nmap) plus a parsed report. To re-parse an existing XML:

python network-scanner\scripts\parse_nmap.py output\nmap\scan.xml --out output\nmap

Produces:

• output/nmap/FINDINGS.md — hosts, open ports, services, versions, plus a severity-ranked Findings section.
• output/nmap/findings.json — structured results (including the derived findings[]) for downstream skills.

The parser derives findings from the scan (best results with --profile vuln or safe-scripts):

• Exposed services — classified by risk (cleartext FTP/Telnet, RDP/VNC, exposed databases, SMB).
• CVEs — pulls CVE-… IDs from vuln/vulners NSE output; VULNERABLE states → critical/high.
• Weak TLS/SSL — SSLv3 / TLS 1.0–1.1 / RC4 / EXPORT / DES / MD5 / low cipher grade.
• Weak SSH — arcfour / CBC / DH group1 / ssh-dss.
• Default / anonymous credentials — ftp-anon, *-default-accounts, brute-found creds.
• EOL / known-bad versions — e.g. vsftpd 2.3.4 backdoor, OpenSSH < 7, Apache 2.2, IIS ≤ 6, PHP 5.

To populate CVE/TLS/SSH/cred findings, run NSE: --profile vuln or --profile safe-scripts.

Notes & Safety

• Timing: service/full on a /24 can take minutes to hours. Start narrow (single host or quick), widen as needed.
• The wrapper refuses dos, exploit, and brute NSE categories by default; passing them requires --allow-intrusive and explicit user authorization.
• All findings are reported for defensive purposes: attack-surface reduction, patching EOL services, closing unnecessary ports, hardening exposed management interfaces (RDP/SSH/SMB).