How Do Viruses Spread?
All the advice you've ever heard about how to avoid getting infected by a computer virus may be wrong. Well, at least some of it... A new study sheds light on how viruses and other malware are most commonly spread in today's Internet environment. Read on for details...
Where Are Viruses Lurking on the Web?
The 2013 Cisco Annual Security Report includes some disturbing data about how malware (viruses, spyware and other nasties) infects millions of computers each year.
The surprising conclusion of the Cisco study is this: All of the advice you’ve received about sticking with known, trusted Web sites seems to be wrong. In fact, the more legitimate a site is, the more likely you are to catch a malware infection from it.
The report found that the vast majority of malware comes from mainstream sites visited by mass audiences, not from shady sites that relatively few people visit. E-commerce sites are 21 times more likely to deliver malware than counterfeit software sites, for example. Viewing an online advertisement, you are 182 times more likely to be served malware than you are when viewing porn.
Cisco looked at some major online applications and the percentage of total malware exposure found on each type:
- Search Engines: 36%
- Online Video: 22%
- Social Networks: 20%
- Advertisements: 13%
- Other: 9%
Obviously, legitimate sites such as Google, Bing, Youtube and Facebook are not trying to give you malware. But malware distributors strive to inject malware into the most popular sites, and the ones that people trust the most. You may be wary of clicking a link on a gambling site if you are not sure what it does, but you might not hesitate to click it while visiting your favorite search engine, online shopping or social media website.
Hackers are constantly looking for vulnerabilities in the software that powers websites. Sloppy coding practices may open the door for "SQL injection attacks," and "buffer overruns." Poor security and weak passwords may allow breaches where malicious code can be planted.
When Malware Attacks...
Once malware infects your computer, it can use your system’s resources to spread itself even further. Malware may access your contacts lists and send phishing links via email to friends and family. It may re-direct browser requests for legitimate websites to rogue sites. Unknown to you, one malware program may download and install others. Malware may copy itself to a networked computer, USB drive or other removable media that you insert into your computer. Email attachments, removable media, free software containing Trojan Horses, and file-sharing on home or office networks still play roles. It’s as important as ever to keep your anti-malware program up to date and practice safe computing habits.
Web exploits are by far the biggest malware vector online. On the plus side, email spam is down 18% worldwide. Mobile malware accounted for only 0.5% of malware exposures in Cisco's Security Report, although Android malware instances increased over 2500% in 2012. (Take that number with a grain of salt, though. A large chunk of the Android malware problem comes from sketchy third-party app markets. See Do You Need Mobile Security Protection? for some additional advice.)
The moral of this story is: keep your guard up no matter where you are online. Don’t ignore the warnings of your anti-malware program just because you’re visiting a site that’s familiar and trusted. It’s entirely possible that site has been infected with malware since your last visit. And remember that you don't have to shell out big bucks for good computer security. See my article Free AntiVirus Programs for a list of free alternatives to Norton, McAfee and other commercial antivirus software.
Have you ever gotten a computer virus from a "good neighborhood" while browsing the Web? What's your strategy for staying safe online?
Posted by Bob Rankin on 14 Mar 2013
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Article information: AskBobRankin -- How Do Viruses Spread? (Posted: 14 Mar 2013)
Copyright © 2005 - Bob Rankin - All Rights Reserved