Introducing the usage of Python-nmap network scanning and sniffing toolkit

nmap concept

NMap, also known as Network Mapper, was originally a network scanning and sniffing toolkit under Linux.

nmap is a network connection scanning software, used to scan open network connections of computers on the Internet. Determine which services are running on which connections and infer which operating system the computer is running (this is also known as fingerprinting). It is one of the must-use software for network administrators and is used to assess network system security.

Like most tools used for network security, nmap is also a tool favored by many hackers and hackers (also known as script kiddies). System administrators can use nmap to detect unauthorized use of servers in the work environment, but hackers will use nmap to collect the network settings of target computers to plan attacks.

Nmap is often confused with Nessus, a system vulnerability assessment software. Nmap uses stealth methods to avoid the surveillance of intrusion detection systems and try not to affect the daily operations of the target system.

Nmap was used by Trinity to hack into the energy management system of power plants in The Matrix, together with the 32-bit cyclic redundancy check vulnerability of SSH1.

nmap function

There are three basic functions. One is to detect whether a group of hosts is online; the second is to scan the host port and sniff the provided network services; and it can also Infer the operating system used by the host. Nmap can be used to scan LANs with as few as two nodes, up to networks with more than 500 nodes. Nmap also allows users to customize scanning techniques. Usually, a simple ping operation using the ICMP protocol can meet general needs; it can also deeply detect the UDP or TCP port, down to the operating system used by the host; it can also record all detection results into logs in various formats for further analysis. Analysis operations.

Perform a ping scan and print out the hosts that responded to the scan without further testing (such as port scanning or operating system detection):

nmap -sP 192.168.1.0/24

Only list each host on the specified network Host, do not send any packets to the target host:

nmap -sL 192.168.1.0/24

To detect the open ports of the target host, you can specify a comma-separated port list (such as -PS22, 23, 25, 80):

nmap -PS 192.168.1.234

Use UDP ping to detect the host:

nmap -PU 192.168.1.0/24

The most frequently used scan option: SYN scan, also known as semi-open scan, it does not open a full TCP connection and executes very quickly:

nmap -sS 192.168.1.0/24

nmap installation

This article takes linux Ubuntu16.04 as an example, and finally mainly uses python to operate

1. Install nmap first

sudo apt-get install nmap

2. Then install python-nmap

sudo pip install python-nmap

After installation, import nmap into python and test to verify whether it is successful

com@pythontab:~# python
Python 2.7.12 (default, Dec  3 2016, 10:42:27) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-17)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import nmap

Python operation nmap

1. Simple Small case

Create a PortScanner instance, and then scan ports 20-443 of the IP 114.114.114.114.

import nmap
nm = nmap.PortScanner()
ret = nm.scan('114.114.114.114','20')
print ret

The return format is as follows:

{
    'nmap': {
        'scanstats': {'uphosts': '1', 'timestr': 'Tue Oct 25 11:30:47 2016', 'downhosts': '0', 'totalhosts': '1', 'elapsed': '1.11'},
        'scaninfo': {'tcp': {'services': '20', 'method': 'connect'}}, 
        'command_line': 'nmap -oX - -p 20 -sV 115.239.210.26'
     },
    'scan': {
        '115.239.210.26': {
            'status': {'state': 'up', 'reason': 'syn-ack'},
            'hostnames': [{'type': '', 'name': ''}],
            'vendor': {}, 
            'addresses': {'ipv4': '115.239.210.26'},
            'tcp': {20: {'product': '', 'state': 'filtered', 'version': '', 'name': 'ftp-data', 'conf': '3', 'extrainfo': '', 'reason': 'no-response', 'cpe': ''}
            }
        }
    }
}

2. Built-in method:

You can also print out simple information

import nmap  
nm = nmap.PortScanner() 
print nm.scaninfo()
# {u'tcp': {'services': u'20-443', 'method': u'syn'}}
print nm.command_line() 
# u'nmap -oX - -p 20-443 -sV 114.114.114.114'

View How many hosts are there

print nm.all_hosts()

[u'114.114.114.114']

View the detailed information of the host

nm['114.114.114.114']

View all protocols included in the host

nm['114.114.114.114'].all_protocols()

Check which ports of the host provide the tcp protocol

nm['114.114.114.114']['tcp']
nm['114.114.114.114']['tcp'].keys()

Check whether the port provides the tcp protocol

nm['114.114.114.114'].has_tcp(21)

You can also set the parameters for nmap execution like this

nm.scan(hosts='192.168.1.0/24', arguments='-n -sP -PE -PA21,23,80,3389')

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