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Nov 21, 2006 in My Shout Outs
There has been recent talks about the youngster who got charged for leeching on someone’s network.
And so many of us will now follow what ST recommends. ie disable SSID broadcast, encrypting WEP etc. Allow me to share some information with you based on my knowledge and expertise in terms of networking and network security.
To me what is really important when you are using your laptop in an open wireless environment is to link up with the right Access Point (AP). With Singapore going wireless island wide, I forsee a problem in the near future. I am sure the technical people behind the wireless experts will do what they can but we as end users need to be aware of the problems too.
So you go to Macdonalds, turn on the wireless device and allow it to roam for available networks. And you see one network that is unsecure. Free internet! WOW!
Not so wow after all. Someone (like me) who has malicious intentions can set up what we term as, a rouge Access Point. It entices people to connect to me cause perhaps, I am the only one offering internet access without the need for a password. And Microsoft allows the system to connect to it automatically unless you disable the feature (it is enabled by default). What happens is, all your internet traffic will go through my access point (which eventually means I have access to all the information that you upload and download onto the web). So you go into Live journal, key in your username and ID and guess who has the password now? You think your internet bank has good encryption when it comes to passwords? It sure does. But I can do something that will install a keylogger into your system, with or without your knowledge. What a keylogger does is that it logs everything you type. So when I view my logs and I see entries such as:
www.dbs.com.sg
princecharlesming
abc123
It doesn’t take a genius to realise what the 3 fields would mean. So in a way the banks issuing tokens are a good idea. But most people use the same password across the board. How many of you actually change your passwords every 3 months, or have different passwords for each account you log into online? Not many I would say. What are the odds that the same user id and password will work on say, live journal? Pretty good. And so I go into live journal, try out the passwords and whola! It works! Guess what sort of entry I would love to type in your name? Potentially the ones that will land you in jail for quite a while. The authorities may come to get me eventually after a long investigation (if I werent’ careful in clearing my tracks) but do you really wanna be arrested and go through court sessions to clear your name when you did nothing?
So that’s one part of it. Be careful when you are out on a public wireless internet. Be VERY careful.
As for home networks, enabling MAC address filtering is a good way to keep unauthorised people out. But you need to know what you are doing or you may lock yourself out. What is a MAC address? It is like the NRIC of your network card. The address is set by the manufacturer and is unique. How do you get the MAC address?
Open up your command prompt and type “cmd”
When the command prompt is up, type “ipconfig /all” (Please ignore the “” when doing the actual input). You shoud see something like :
Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.
H:\>ipconfig /all
Windows IP Configuration
Host Name . . . . . . . . . . . . : xxx
Primary Dns Suffix . . . . . . . : xxx
Node Type . . . . . . . . . . . . : xxx
IP Routing Enabled. . . . . . . . : xx
WINS Proxy Enabled. . . . . . . . : xx
DNS Suffix Search List. . . . . . : xxx
xx
xxx
Ethernet adapter Local Area Connection:
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Intel(R) PRO/100 VM Network Connecti
on #2
Physical Address. . . . . . . . . : 00-08-02-7D-55-0E
Dhcp Enabled. . . . . . . . . . . : xx
IP Address. . . . . . . . . . . . : xx
Subnet Mask . . . . . . . . . . . : xx
Default Gateway . . . . . . . . . : xx
DNS Servers . . . . . . . . . . . : xx
xx
I have put in xxx for the details that I need to hide (for security reasons) and details that don’t matter anyway. Look at the Physical Address field. That is your MAC address. When you are in your router configuration (please follow the instructions in the manual that you get when you purchase your wireless router), look for the place that enables MAC filtering and key in that address into the field provided. Don’t forget to save.
BE VERY CAREFUL not to key incorrectly. The consequence is that you will lose your connection to that router. A
After enabling MAC filtering, what this means is, only the machine with the MAC address listed will be allowed through. Let’s go through some scenarios :
1. If you change your wireless network card, will your connection still work? NO. You will need to go through the same process above again.
2. If you take out the wireless card and put it into another machine (say your friend’s laptop who is visiting), will it work on his/her? YES. Remember the setting is tied to that hardware, not anything else.
Some other pointers:
1. Please change your default password as soon as you can. I cannot stress this enough.
2. Set your SSID to something else other than the default setting. Hmm I have mixed feelings when it comes to this. The way I see it, what it does is, it stops genuine novice users from connecting easily (your parents/brother who wants to use the network at home for the first time may have problems). As an intruder or the technically trained, they will know there is a point some where. They will have problems finding out where when they do a scan BUT it won’t take more than 2 or 3 seconds on normal occasions to find the same SSID (even if you encrypt it) in clear text. You can encrypt your SSID, but if your network is in use and there is a lot of traffic going in and out, I will be able to see that same encrypted SSID in mere seconds. I don’t really need tools for that. It is just the way the network functions. I won’t go into the technical aspects, but just be aware that it can be done. For those who wanna go deeper in this, I am willng to.
That’s all for now! Have a jolly Christmas this season!
Meantime, as what someone would say, Be Good. Else, be safe.