Practical Linux home security

David M Williams
Sunday, 25 May 2008 14:46

Opinion and Analysis

Microsoft has attempted to correct this terrible flaw within Windows Vista via user access control (UAC). However, I doubt anyone need look far to find complaints of dissatisfaction with how UAC works. This may not be Microsoft’s fault so much, but rather a lot of software still places unreasonable demands for administrative access that UAC prompts appear excessive. The option exists to disable UAC anyway, which renders the system just as vulnerable as previous versions of Windows anyway.

So, the result is you have millions of Windows users running Outlook and Internet Explorer as the super user of their computer. Any program they run – whether good or bad – has full unfettered access to the system. By contrast, you simply don’t find Linux users typing “sudo firefox.”

All this said, one thing which doesn’t vary based on your operating system is the requirement for a firewall. This piece of software restricts incoming and/or outgoing Internet traffic. You may run a web site for internal use but you don’t want it exposed to the outside world. In this case, blocking port 80 on your firewall will prevent anybody browsing your site that is not inside your network.

In reality, you ought to block all Internet traffic by default and then enable the ports you wish to use. This means you know precisely what has been permitted and you will be protected in the event your system is running services you weren’t aware of – like ftp and web and mail servers, for instance. A firewall can also serve to protect you from denial of service attacks.

Another crucial piece of software in this modern world is an anti-spam system. No matter where you are or what you run you’ll be targeted by Viagra salespeople and the relatives of dead royalty who have access to untold millions if you’ll just send them some cash. A lot of spam doesn’t even make sense; I got an advertisement for penile enlargement but when I read it I couldn’t see anything about making our prisons larger. Perhaps I misunderstood.

So, let’s wrap up. There’s three items that are important in home computer security – anti-virus, firewall and anti-spam. Linux is a safer system than Windows; this is not rhetoric but is due to different designs and the “correct” way to work drummed into end users. Nevertheless, if you wish to connect to any other computer you’re doing the best thing by keeping everyone’s safety in mind.

For Linux, a good free and open source anti-virus system is ClamAV. An excellent firewall is already built in, called iptables. It can be tricky to configure in which case you might like to check out L7 Filter. For anti-spam try the Anti-Spam SMTP Proxy (ASSP).

Be vigilant, be safe. And let’s hear your thoughts. Do you think there’s any other mandatory category of item for home computer security? Any better software recommendations? Or do you think it’s all a waste of time and anti-virus simply taxes your processor unnecessarily?