Free Antivirus Software

For a while, I worked for an antivirus software company, which leads me to understand malware and viruses better than most. Antivirus software is the rare category of software that I’ll not just pay for, but keep paying for, because antivirus software is software that continually costs money to maintain. Somebody has to keep virus signatures and detection methods up to date, or the software quickly decays and becomes worthless — unlike some software which I’ve been using for more than ten years without changing — once it works, it works.

Open source anti-virus software is a particularly rare category of software because of the resources it takes (not to mention the possibility that virus authors will examine the anti-virus code to help their creations elude detection.) With this in mind, anti-virus software tends to be heavily commercial, heavily advertised, and it’s difficult to find the free solutions that are out there. Luckily, there are a few good ones, which work well for those of us who would prefer to avoid spending money we don’t have to, especially on systems that aren’t at much risk.

MoonSecure is the first one on my list. It’s a real-time scanner built on the ClamAV engine, which is quite a good Unix scanning engine in its own right.  ClamAV has Windows binaries and a periodic scanning engine as well, but lacks the “real-time” scanning component, which is probably more appropriately termed “scanning on the fly.”  By all appearances, it’s entirely non-commercial, and it’s the only one in this list that installs cleanly on a server version of Windows without complaint.

ClamAV deserves its own mention, because it has its own Windows binaries and also installs on a server and is non-commercial in nature.  Also, according to the MoonSecure people, MoonSecure is developing their own engine.

Grisoft’s AVG is next on the list, free for non-commercial use, and supported by its more-capable, non-free counterparts.  It does a decent job on a desktop; it won’t install on a server.  You have to get a license key and have a valid email address.

Avast! is similar in many ways, being free, and supported by its professional non-free counterpart.  Once a year or so, you have to get a new license number — which is free.  Despite its weird annual license renewal and terrifically loud “virus database updated,” I do have a particular fondness for this one.

Avira’s Antivir fits neatly into the same category.  However, it also has a daily pop-up that’s quite irritating.  It’s not too hard to disable, frankly, but it might be violating their license.   I’d pick something else for this reason alone, but otherwise, not too bad.

PC Tools Antivirus is also in the same category, and pretty decent all around.  Having used it the least, I don’t have a lot to say about it, but I include it here for completeness.