posted by Alcibiades on Wed 4th Jan 2006 18:04 UTC
IconLike a lot of people who have worked in the business, I find myself in conversations about computer security with people who are having problems or know people who have problems. I wrote this to save me from explaining the same thing over and over again to different people, and to save them the trouble of having to make notes as we talked. It was meant to be something you could give to a 'naive user' and have them be able to read and follow it more or less unaided, and while not being a complete guide, at least be something that made them more secure than before they got it.

What is the danger?

That a machine will have 'malware' loaded onto it. This will then allow criminals to use it to send spam (often promoting pornography), hack other computers, make it dial up premium rate numbers, or steal information from it, including bank account numbers and passwords. In bad cases bank accounts can be stolen, in extreme cases identity theft is possible. The risks are mainly financial, but if a machine is captured by pornographers, they may also be legal. In the UK, for example, the existence of some kinds of material on a computer is going to be a strict liability offence. The onus is going to be on the holder to prove he/she was not the agent/owner, and it may not be easy.

How bad is it?

Bad and worsening. Here is one example. USA Today, in November 2004, set up 6 machines on the net and observed the results. In two weeks they attracted 306,000 attacks, and an XP SP1 machine was broken into in four minutes. The Denver Post did the same thing in February 2005, and attracted 45,000 attacks in a week. This is the risk from simply being connected. To it, you have to add user actions - unwittingly visiting fraudulent and malicious sites, receiving malicious emails or attachments. There have been 100,000+ Windows viruses, 2,500 Windows spyware releases, and some studies show 80% of home PCs may be infected with spyware broadly defined. The latest thing is Windows rootkits - essentially undetectable infections.

Who is at risk, and from who?

Anyone connecting to the net with Windows 95, 98, ME, or XP with Service Pack 1 or lower. Broadband makes the risk much greater. Fully up to date versions of XP SP2 are much less at risk. People running Unix based systems (including MacOS and Linux flavours) are much less at risk. People running firewalls are also much less at risk.

Basically, connect Windows XP SP1, 98 or 95 to the net without a firewall, and the evidence is, you'll likely be hacked within an hour. You are almost certain to get infected if you (or your children) use music sharing software, or if you agree to download and install software as a condition for free access to some kinds of services. Downloading ring tones for mobiles is a common source of infection. Downloading bootleg software (so called warez) is another.

You can find out how secure your machine is to some kinds of attacks by going to Steve Gibson's Shields Up site: (go to the Shields Up section) to test the vulnerability of your firewall and system. Recommended. This tells you about liability to incoming attacks. Leak Test, from the same site, will tell you whether your firewall protects from outbound leakage.

The perpetrators are mostly criminals in it for profit. The days of the amateur teenage hacker in a suburban bedroom are over.

If I follow these recommendations am I safe?

No. You are safer. You are still running an Operating System with a proven record of security faults in a network environment. And this guide is not a complete account of the subject.

Are there alternatives to these recommendations?

Yes. Plan B is: go to a Unix based Operating System, like Linux or MacOS or one of the BSDs. Here are some thoughts on this one.

It helps because there's been far less malware. Probably under 50 real viruses for both MacOS and Linux, even less for Commercial Unix. Spyware is so far unknown (according to Webroot).

Linux or BSD will run on your existing machine side by side with Windows. It is also free, so this is the cheapest of the Plans B. However, don't try moving to Linux or a BSD without help. Your helper should agree to be available for support for six months after the installation. MacOS, which is similarly or maybe more secure, and also Unix based, one probably can do unaided. But you need a whole new computer for it, and new versions of your applications, so it gets expensive. The Mac Mini is worth considering if you are tempted.

The best bet in Linux/Unix for the end user is probably PCLinux, available free for download over the net as a single CD iso. Mepis is also very good. Either will come, free, with all the applications you are likely to need, including Office packages. Maybe fewer games than you would like. In BSDs, PCBSD and DesktopBSD are end-user oriented distributions. They are so far a lot less popular than the Linuxes.

How to safeguard Windows? Four rules go a long way.

Rule 1. Use a limited user account for normal work, and for connection to the net. Never connect from an account with administration privileges.

How to do this. Use the Users and Passwords control panel to create a new Administrator account. Reset your current account to limited user. Then only use the Administrator account to manage the system, install software etc, and then sign off. Never connect to the net when signed on as Administrator, except to do Windows Update. Enable privacy between user accounts, and have separate user accounts for everyone who uses the computer. Make a separate dedicated limited user account for shopping & banking.

Why this helps. Any attacks made on you while on the net will have the same privileges as the account you signed on with. (There have been some exceptions, but this is mostly true for up to date systems). Administrator accounts can do anything at all to the system. Limited user accounts can do relatively little. Signing on as a limited user restricts the attacker's options. Microsoft's default on this is for you to sign on as administrator. It is as if, in an hotel, every guest key opened all guest rooms and the main safe, kitchen and boiler room as well. Change it.

Note1: Windows 9x has only one account, so this won't work with 95 or 98 or ME. Either upgrade to XP, but its not simple, or consider buying Anti-Executable from Learn to use it to lock down your machine. Note that I have not used this package - the recommendation comes from the product specification, user guide, and testimonials. Also use ZoneAlarm (below) to disconnect from Broadband when not actively using it.

Note2: Some older software, and all CD burning software, will have problems running as a limited user. Use the 'run as' function (right click on the program icon) to run them as Administrator.

Rule 2. Connect to Broadband via an ADSL Router, never just an ADSL modem.

How to do this. Either ask your provider to supply Broadband with an ADSL Router, or buy a combined modem/router yourself (cheapest by mail order). Make sure you have the right PC ports to connect it up and that you get cables. If you have a choice, use an Ethernet connection, in preference to USB. Find out how to address the hardware firewall it will have in it, and set it to high protection if it isn't already.

Why this helps. If you just connect via a modem, your machine will be visible to hackers worldwide. If you use a Router, it will use a private address for your machine, and the only thing visible on the net will be the Router (a much harder target). If you set the hardware firewall to high, the router also will be invisible.

Table of contents
  1. "Securing Windows 1/2"
  2. "Securing Windows 2/2"
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