Report: Newer Windows Versions Are Less Susceptible to Malware

The more recent your copy of Windows, the more likely it is to be secure and free of dangerous malware.

That information comes from Tim Rains, Microsoft's Chief Security Advisor. He blogged about data culled from the latest Microsoft Security Intelligence Report. The report covers malware (bad stuff like computer worms and viruses) for the third and fourth quarters of 2014, i.e. the last half of 2014, and how often it infected Windows computers.

The results covered Windows operating systems (OSes) from the most recent, Windows 8.1, back to Windows Vista Service Pack 2 (SP2). The least-infected OS was Windows 8.1, followed by each previous version: Windows 8, Windows 7 and finally Windows Vista.

The data was "normalized," meaning it was calculated by comparing an equal number of computers per version; in this case, it was 1,000 computers for each version. The final number means how many computers were infected per 1,000 computers -- so an infection rate of 10, for example, would mean 10 computers out of 1,000 running a particular OS would have some kind of malware in it.

Windows 8.1 Gets a Gold Star

The report shows Windows 8.1 with an infection rate of 1.3 for Q4 2014, the period from October-December. For the previous quarter, covering July-September, the rate of infected Windows 8.1 computers was 1.8.

For Windows 8, the numbers were significantly higher: 5.0 for Q4 2014, and 6.7 for Q3. For Windows 7, it was 6.0 for Q4 and 9.1 for Q3.

And Windows Vista suffered an infection rate of 5.2 for Q4, and a whopping 10.4 for Q3. Interestingly, the much-reviled Vista had a lower rate of infection in Q4 than the much-loved Windows 7.

(As a side note, Windows Server, which is typically run in datacenters, has a very low rate of infection, but holds to the same pattern of more recent versions having fewer infections. Servers aren't usually used to surf the Web, which is where a great deal of malware is picked up.)

Trojans and Worms

The two largest categories of malware that infect Windows computers are Trojans and worms. A Trojan tries to trick the user into downloading what appears to be a harmless or helpful program, but is in reality a harmful piece of software. A case I have personal experience with involved a popup on a computer that said the user's copy of Windows was compromised, and to download the program to which it linked to eliminate the malicious software. Of course, it was the downloaded program itself that caused the infection.

A worm is a program that can cause harm in various ways, by erasing files or doing some other harm. It then propagates itself, spreading to other computers. The main difference between a worm and a virus, another type of malware, is that a worm doesn't require any human action to infect a system, whereas a virus typically needs a person to download a dangerous program, often a harmful email attachment. About.com has a site dedicated to the topic of Internet and general computer security.

Newer Is Better

Rains drew the following conclusion from the data:

"Some of the CISOs and IT professionals I talk to use this operating system infection rate data to help make a business case for upgrading to newer, more secure software or deploying more secure service packs for their current platforms. As you can see from the latest data, newer is better across the board."

That's good advice, and something others should heed. Like newer cars with better technology that are generally safer, with devices like backup cameras, blind-spot sensors and more airbags, newer Microsoft OSes are better at protecting you from malware.