flan-go-scan

README

flan

A network scanner in Go. Successor to Flan Scan.

Features

• TCP port scanning with bounded concurrency
• 51-protocol service fingerprinting via fingerprintx (SSH, HTTP, MySQL, Redis, RDP, PostgreSQL, and more)
• Technology detection (Wappalyzer) and CPE generation
• TLS certificate inspection (version, cipher, subject, issuer, SANs, expiry, self-signed)
• CVE lookup by CPE via NVD API
• Host discovery (TCP probe to skip dead hosts)
• Passive subdomain enumeration via 9 no-key sources (crt.sh, Common Crawl, Wayback Machine, RapidDNS, Anubis, Digitorus, HudsonRock, SiteDossier, THC)
• CDN detection (Cloudflare) — limits scan to ports 80/443 by default on CDN hosts
• DNS enumeration with wildcard detection and custom wordlist/resolver support
• NS, MX, TXT, CNAME record lookups
• CIDR and stdin input support
• nmap top 100/1000 port lists
• Scan checkpointing and resumption
• Progress reporting
• Graceful shutdown on SIGINT/SIGTERM
• AI-powered security analysis via Together API (DeepSeek V3.1)
• JSON, JSONL (streaming), CSV, and text output
• Configurable via YAML

Installation

From GitHub:

go install github.com/therandomsecurityguy/flan-go-scan/cmd/flan@latest

From source (go version > 1.21):

git clone git@github.com:therandomsecurityguy/flan-go-scan.git
cd flan-go-scan
go build -o flan ./cmd/flan
./flan --help

Docker:

git clone git@github.com:therandomsecurityguy/flan-go-scan.git
cd flan-go-scan
docker build -t flan .
docker run --rm flan --help
docker run --rm flan -t scanme.nmap.org --json

Usage

flan --help

Scan a single target:

flan -t scanme.nmap.org

Scan a domain (DNS enumeration + port scan):

flan -d example.com

Scan from a file with top 1000 ports:

flan -l targets.txt --top-ports 1000

Scan a CIDR range from stdin:

echo "10.0.0.0/24" | flan -l -

Scan with custom wordlist and resolver:

flan -d example.com -w wordlist.txt -r 8.8.8.8:53

Passive enumeration only (skip brute-force):

flan -d example.com --passive-only

Scan all ports on CDN hosts (default is 80/443 only):

flan -d example.com --scan-cdn

Scan with AI-powered analysis (requires TOGETHER_API_KEY):

flan -t scanme.nmap.org --analyze

Flags

Flag	Description
-t	Target host/IP
-l	Target file (default ips.txt, - for stdin)
-d	Domain to enumerate via DNS
-p	Ports to scan
--top-ports	Use nmap top port list: 100 or 1000
-c	Config file (default config/config.yaml)
-w	Custom DNS subdomain wordlist
-r	Custom DNS resolver (ip:port)
--passive-only	Skip brute-force, use passive sources only
--scan-cdn	Scan all ports on CDN hosts (default: 80/443 only)
--analyze	AI security analysis via Together API (requires TOGETHER_API_KEY)
--json	JSON output
--jsonl	JSONL streaming output
--csv	CSV output

Tests

go test ./... -v

License

BSD 3-Clause License