Social Engineering Tops Security Flaw Exploits as Malware Vector

Social-engineering attacks are increasing, and users need to be more vigilant about what they are opening and downloading.

Social-engineering attacks in which users are tricked into clicking on a link or downloading malicious programs are far more common than attacks that exploit security vulnerabilities in software, according to Microsoft.

One out of every 14 programs downloaded by Windows users later were discovered to be malicious, Jeb Haber, program manager lead of the SmartScreen group working on Internet Explorer at Microsoft, wrote May 17 on the IE blog. Internet Explorer blocked between 2 million and 5 million attacks a day for Internet Explorer 8 and 9 customers who have enabled the SmartScreen filter protection, Microsoft said.

"User-downloaded malware is a huge problem and getting bigger," Haber said.

Originally, SmartScreen in Internet Explorer 7 was a URL-based filter that obtained lists of bad URLs from a cloud-based URL-reputation service, according to Microsoft. Internet Explorer 8 enhanced SmartScreen to filter out sites that had social-engineering techniques. Other major browsers, including Google Chrome and Firefox Mozilla, also display similar warnings for potential rogue Websites.

Modern Web browsers are generally more secure than they used to be, and software vendors are getting better about automatically pushing out patches to fix bugs, Haber said, forcing attackers to switch tactics to use more social-engineering tricks.

Social-engineering tactics are combined with other attack vectors, such as spam or poisoned links on search results pages. The Koobface worm proliferated on Facebook because users saw a message from friends about a cool video to watch. When the user tried to watch the video, they were instructed to download software that would allow the video to play, but it was actually malware. There were similar scams for videos purporting to show the operation that killed Osama bin Laden earlier this month, as well.

It's not just Windows users falling for social-engineering tricks. Mac users are, as well. With MacDefender, MacSecurity and MacProtector fake antivirus on the scene, many Mac users are falling for the scam, according to Mac security company Intego. "We are contacted by a huge number of customers who are worried about this fake antivirus, and have dozens of samples, including a number of variants of the scareware," the company posted on its Mac Security Blog.

ZDNet's Ed Bott posted a transcript of his interview with an AppleCare support representative that confirmed that Apple's call centers are hearing from many users whose machines are infected with MacDefender and its variants. "It started with one call a day two weeks ago; now it's every other call. It's getting worse. And quick," the AppleCare representative told Bott.

To help protect users from social-engineering attacks where users are being conned into downloading files, Microsoft expanded SmartScreen in Internet Explorer 9 with Application Reputation. Application Reputation looks at what is being downloaded and informs users if they are unknown or potentially untrustworthy. "When it comes to program downloads, other browsers today either warn on every file or don't warn at all," Haber said.

Application Reputation alone will prevent more than 20 million additional infections per month, and that's not counting the URLs blocked by the SmartScreen filters, according to Haber. Users sometimes see warnings for legitimate software, but that's only because it is new and "has not yet established a reputation" but that is a "rare exception," according to Haber. Unsigned programs were the cause of 96 percent of the warnings that consumers have seen to date and the remaining 4 percent were the result of Website certificates that had previously been associated with malware or were newly issued.

Even with Application Reputation in place, about 5 percent of users ignore the warnings and download malicious applications anyway, according to Microsoft. On any given day, clicking through the "unknown" warning page carries a risk between 25 percent and 70 percent of actually getting a malware infection, according to Haber. A typical user will only see a couple of these warnings each year, so it's best to take them very seriously.