Web surfers don't have to indulge in risky behavior to paint a bull's eye on their browser for byte bandits.
That's one of the findings in the annual security report released this week by Cisco.
Despite popular assumptions that security risks grow as a person's online activity becomes shadier, the report said, "the highest concentration of online security threats do not target pornography, pharmaceutical or gambling sites as much as they do legitimate destinations visited by mass audiences, such as major search engines, retail sites and social media outlets."
For example, online shopping sites are 21 times as likely to deliver malicious content than a counterfeit software site. The likelihood is even higher for search engines -- they're 27 times as likely to deliver malware than a bogus software site.
Advertisements, ubiquitous on the Web, are 182 as times likely to deliver malicious content than smut sites, the report added. In fact, malicious advertising, or malvertising, played a more significant role in Web malware in 2012 than in 2011, Cisco said.
"[W]eb malware encounters most frequently occur via normal browsing of legitimate websites that may have been compromised or are unwittingly serving malicious advertising," the report said. "Malicious advertising can impact any website, regardless of the site's origin."
What makes malvertising particularly pernicious is that it can push malware to the visitor of a web page without any interaction with the ad itself.
Malvertising typically does that by exploiting known browser vulnerabilities. "If a user visits a site with malicious advertising on it, it can force malware through the recent Java vulnerability to the desktop without the user knowing," George Tubin, a senior security strategist, with Trusteer, a Boston-based endpoint security company, said in an interview. Oracle recently patched zero-day flaws in Java.
Because malvertising usually targets known vulnerabilities, an enterprise can do much to protect its users by ensuring their software is up-to-date, said Chris Larsen, a senior malware researcher with security company Blue Coat, of Sunnyvale, Calif. Key software programs that should be kept current are the operating system, the browser, Java, Adobe Flash and Adobe Acrobat Reader.
"If those are patched against known attacks, most of the time malvertising will not get you," Larsen said.
In addition to keeping programs updated, security on the desktop and at the Internet connection point is important, he said. Larsen recommended an antivirus program that recognizes exploit activity and can identify the signatures of bad apps, along with a malware-aware Web filter at an organization's gateway.
The Cisco report noted that one of the biggest challenges to any organization is dealing with an "any-to-any" world. "The crux of the any-to-any issue is this: We're quickly reaching the point where it is increasingly less likely that a user is going to access a business through an enterprise network," Chris Young, senior vice president of the security and government group at Cisco, said in the report.
While that development isn't unexpected, companies may remain unprepared for it from a security perspective. The issue has significant consequences for security professionals, especially in light of the Bring-Your-Own-Device revolution. "With the rapid adoption of BYOD," the report said, "the reality of multiple devices per user and growth of cloud-based services, the era of managing security capabilities on each endpoint is over."
Read more about security awareness in CSOonline's Security Awareness section.