This only shows the very basics of what can happen if your network is scanned. Remember, protect your data at all times.
Malicious users have a plethora of programs that can be downloaded from the web. Remember, the next time you are at the airport, in a hotel or at your favorite coffee shop or hotspot, someone could be scanning you. These programs can also be used to protect your network. The key behind protecting your computers and data is using the programs on your network to see what a malicious user sees. Here’s three programs that are not intended for malicious use. Their intentions are for scanning or protecting your network.
Netscan is used to inventory computers on your network and can be used to navigate to computers. If this software is misused by a user, it can give targets to them. How do you keep your computers safe? Operating system updates, application updates, enabling your firewall, using a hardware firewall, complex passwords, properly shared files and folders, disabling telnet and other services and changing passwords. (basics)
(The ip addresses, netbios names and mac addresses have been changed in the example below)
Once a malicious user finds your computers (above), he or she can then run Zenmap to scan your computers. Zenmap is a security tool that scans a computer or a network of computers and can be used to show open ports along with what type of operating system (along with other information) is loaded on the pc.
(The above computers during this exercise show open ports and services that are normally closed or not installed)
Zenmap can scan computers, routers, access points, printers, NASs, tablets, notebooks and other network devices to show open ports and other information about any network device. The above example is a quick scan on Zenmap. Zenmap is a very complex software that has dozens of features.
How is this information used? This information ‘shows’ the malicious user what ports may be open and it can be used to tell what the target operating system is along with dozens of more details about the system. How do you protect yourself? Use the methods listed above on netscan. Systems can also be further hardened by following steps recommended on this blog.
A gifted hacker can use Wireshark to now sniff targets to try to capture password, see where you are surfing or find detailed packet information. Wireshark is a protocol analyzer that can be used to protect your network. Use a VPN service when traveling and make sure you use https when searching Google, using social sites such as Facebook and never transmit in plain text (Use VPNs). You in turn can use this software to protect your network by seeing what information is being given out. Take appropriate precautions.
Wireshark is also an excellent program that can be used with filters to find torrents, viruses and malicious activity on your network. (Capture filters, Windumps and an analyzer are also available)
While this is the very basics of this software, this software is NOT meant to be used in a manner other than what it was designed for. Using these tools to analyze your network can help to protect your data. Using these tools against a network can also be illegal if you do not own all of the equipment on the network or you do NOT have permission to do so.
Update – Here’s a great scanner used by Rick over at What’s On My PC -
If you are into networking, you most likely have heard of Radmin Remote Access Software. To promote Radmin, I noticed that they offer a FREE IP Scanner called Advanced IP Scanner that is helpful in locating and monitoring the devices (wired or wireless) that are connected to your network (home or business). Scanners such as this is helpful in identifying the IP addresses (which dynamically can change) and MAC Addresses of those devices. Years ago when I managed a network, I used an IP scanner such as this to make sure all of my network devices and computers were alive and functioning properly….read more (Go over and check out the video)