Kaspersky researchers announced today (January 23) on their official blog that approximately 30% of the Mac malware attacks detected by Kaspersky anti-virus software last year were caused by a single malvertising Trojan.

We have previously reported on the Shlayer Mac Trojan, and there is little sign of it going away. In a press release, the company said that one in ten Macs running Kaspersky anti-virus software for Macs has encountered Shlayer.

Of the top 10 most common Mac threats encountered by Mac users, most were adware that Shlayer itself downloads and installs via secondary infection. [According to Kaspersky researchers, links to Shlayer-infected pages appear in user-submitted content on YouTube and Wikipedia, often because the owners of certain legitimate sites let their registrations lapse and criminals snatch them.

Fans of sports and video streaming are especially susceptible. This is because Shlayer often masquerades as Adobe Flash Player or other video software. Shlayer also appears in malicious online advertisements.

Once infected with Shlayer, more ads pop up on the screen, some of which tell you that you are infected and need to purchase (fake) antivirus software. Search results may be hijacked by strange search engines, and your browsing habits may be tracked by more people than usual.

The silver lining is that Shlayer, despite being malware, is so far only interested in adware proliferation. However, it could easily flip the switch and start installing truly dangerous Mac malware.

To avoid being infected by Shlayer or any kind of Mac malware, make sure you are using the best Mac antivirus software.

If you get a dialog box saying that you need to update your Adobe Flash Player,https://get.adobe.com/flashplayer/にあるAdobeの公式ページにアクセスしてください。聞いたこともないビデオプレーヤーをインストールするよう求められたら、インストールしないこと。