go-lanscan

A network cli and golang package that allows you to perform arp and syn scanning on a local area network.

Cli Usage

Prerequisites

First you must install the following dependencies

• golang
• libpcap
  • mac - brew install libpcap
  • linux/debian - sudo apt update && sudo apt install -y libpcap-dev

Installation

Once dependencies are installed, run the following command to install go-lanscan

go install github.com/robgonnella/go-lanscan@latest

Pre-built Binaries

Some pre-built binaries are provided in the releases section of github: https://github.com/robgonnella/go-lanscan/releases. These binaries still have a prerequisite on libpcap being installed first.

Docker

A docker image is provided with go-lanscan prebuilt. https://hub.docker.com/r/rgonnella/go-lanscan

See docker-compose.yml for an example setup.

Linux

docker run --rm --network host -v $(pwd)/reports:/reports rgonnella/go-lanscan:latest

MacOS

On MacOS, host network does not work so you will only be able to scan whatever docker network the container is in. See docker-compose.yml for an example.

docker run --rm -v $(pwd)/reports:/reports rgonnella/go-lanscan:latest

Usage

# print usage info for this cli
go-lanscan --help

# scan all ports on current LAN
sudo go-lanscan

# scan specific ports
sudo go-lanscan --ports 22,111,3000-9000

# scan specific targets   single ip          ip range          cidr
sudo go-lanscan --targets 192.22.22.1,192.168.1.1-192.168.1.50,192.56.42.1/24

# include vendor look-ups on mac addresses (scan will be a little slower)
sudo go-lanscan --vendor

# include reverse dns lookup for hostnames
sudo go-lanscan --hostnames

# update static database used for vendor lookups
# static file is located at ~/.config/go-lanscan/oui.txt
sudo go-lanscan update-vendors

# choose specific interface when scanning
sudo go-lanscan --interface en0

# only output final result as table text
sudo go-lanscan --no-progress

# only output final result in json
sudo go-lanscan --no-progress --json

# run only arp scanning (skip syn scanning)
sudo go-lanscan --arp-only

# set timing - this is how fast packets are sent to hosts
# default is 100µs between packets
# the faster you send packets (shorter the timing), the less accurate the results will be
sudo go-lanscan --timing 1ms # set to 1 millisecond
sudo go-lanscan --timing 500µs # set to 500 microseconds
sudo go-lanscan --timing 500us # alternate symbol for microseconds

Package Usage

Prerequisites

First you must install the following dependencies

• libpcap
  • mac - brew install libpcap
  • linux/debian - sudo apt update && sudo apt install -y libpcap-dev

Example Usage

• arp-scanner
• syn-scanner
• full-scanner

Package Options

You can provide the following options to all scanners

• Provide specific timing duration

This option is used to set a specific time to wait between sending packets to hosts. The default is 100µs. The shorter the timing, the faster packets will be sent, and the less accurate your results will be

  timing := time.Microsecond * 200

  fullScanner := scanner.NewFullScanner(
		netInfo,
		targets,
		ports,
		listenPort,
		scanner.WithTiming(timing),
  )

  // or
  fullScanner.SetTiming(timing)

  // or
  option := scanner.WithTiming(timing)
  option(fullScanner)

• Provide channel for notifications when packet requests are sent to target

  requests := make(chan *scanner.Request)

  synScanner := scanner.NewSynScanner(
    targets,
    netInfo,
    ports,
    listenPort,
    synResults,
    synDone,
    scanner.WithRequestNotifications(requests),
  )

  // or
  synScanner.SetRequestNotifications(requests)

  // or
  option := scanner.WithRequestNotifications(requests)
  option(synScanner)

• Provide your own idle timeout. If no packets are received from our targets for this duration, a timeout occurs and the scanner is marked done

  arpScanner := scanner.NewArpScanner(
    targets,
    netInfo,
    arpResults,
    arpDone,
    scanner.WithIdleTimeout(time.Second*10)
  )

  // or
  arpScanner.SetIdleTimeout(time.Second*10)

  // or
  option := scanner.WithIdleTimeout(time.Second*10)
  option(arpScanner)

• The next option performs vendor look-ups for mac addresses and can only be applied to arpScanner and fullScanner. Vendor lookup is performed by downloading a static database from https://standards-oui.ieee.org/oui/oui.txt and performing queries against this file. The file is stored at ~/.config/go-lanscan/oui.txt

  import (
    ...
    "github.com/robgonnella/go-lanscan/pkg/oui"
  )

  vendorRepo, err := oui.GetDefaultVendorRepo()

  if err != nil {
    panic(err)
  }

  arpScanner := scanner.NewArpScanner(
    targets,
    netInfo,
    arpResults,
    arpDone,
    scanner.WithVendorInfo(vendorRepo)
  )

  // or
  arpScanner.IncludeVendorInfo(vendorRepo)

  // or
  option := scanner.WithVendorInfo(vendorRepo)
  option(arpScanner)

• Perform reverse dns lookup to find hostnames for found devices

  arpScanner := scanner.NewArpScanner(
    targets,
    netInfo,
    arpResults,
    arpDone,
    scanner.WithHostnames(true)
  )

  // or
  arpScanner.IncludeHostnames(true)

  // or
  option := scanner.WithHostnames(true)
  option(arpScanner)