Network Security guide for the home or small business network – Part 10 – use good passwords
In a small, trusted network you might be able to get away with weak passwords for file sharing for instance. What’s a weak password? Anything you might find in a dictionary. Most people don’t realize this, but there are programs designed to crack passwords. They’re designed to take a dictionary file and run through it trying every combination possible. It might take a while, but this kind of brute force attack can be VERY effective against a weak password.
Ahh – you say, but I use a tough password, I use the number 1 after the dictionary word. I’ve got news…. they know, there are cracker programs that will take the dictionary words, try those, then those plus numbers, other characters, two dictionary words, words seperated by a number. Anything that involves either 1) only numbers or 2)one or more simple dictionary words is a weak password.
The reason I include number only passwords is because there are so few combinations possible (10) for each character vs. 10+26 for text+alphabet (and then adding in other characters can help too.)
If it’s a trusted network and the service isn’t available from the outside world. Then, I’m likely to be a bit less picky about strong passwords. Especially if the network is comprised only of trusted users, no public access, etc. In other words good physical security can mean internal services can use weak passwords without great risk. However…. since you need to learn to use hard passwords…. there’s no better place…
Anything accessible from the outside world needs a hard password assigned to it. (Preferrably changed on a frequent basis (every 6 months?) (This is something that’s up to you, more frequently can be a stricter, more secure approach, less frequently can be more convenient for end-users.))
What makes a good hard password? A good mix of letters numbers and characters… 5uP89$Q1 Notice that I mixed upper and lower case (passwords usually ARE case sensitive (which adds ANOTHER 26 possibilites per character…)). Some find that they can make passwords from an easy to remember phrase. (Using the first character of each word.) “The sun is bright but the ice is slippery” for instance might quickly become tsibbtiis – ok – but that’s all letters… hmmmm we’ve got a couple of duplicate letters – how about if bb becomes b2 and ii becomes i2 (tsib2ti2s) Not bad… Maybe I’ll capitalize the first letter and the last letter… (Tsib2ti2S) better…. maybe I could substitute a dollar sign ($) for the first s… T$ib2ti2S, (or a 1 for the first i…) T$1b2ti2S That should give you some good ideas.