This year, Google has been implementing many previously announced security policies, one of which involves the scalable vector graphics (SVG) image format.
Cybercriminals Respond With SVG Image Attacks
Malware authors will surely find new ways to attach harmful JS files to emails. In fact, they may have already zeroed in on a delivery method that first appeared in a spam campaign last November targeting Facebook users in France, according to Bleeping Computer.
An SVG image file usually contains graphical data, but it can also run any embedded JS present in the file. The poisoned SVG file used in the Facebook attack redirected victims’ browsers to a fake website designed to steal login credentials.
SVG images work by default with Internet Explorer (IE). IE has proven to be wide open to JS-based exploitation, so it is no surprise that the browser can be easily directed to a malware-controlled site.
SVG Image Attacks Surge
Another Bleeping Computer article reported that security firms have detected an uptick in SVG image attacks in the past few weeks. In a recent campaign, for example, Japanese targets received legitimate-looking, seemingly business-oriented emails that contained .zip attachments.
These attachments opened malicious SVG files designed to launch a page that prompted victims to download an .exe file. If downloaded and opened, the file installed the Ursnif Trojan. While the SVG file did not specifically conduct the attack, it explicitly facilitated one.
Consider Following Google’s Lead
As a data structure, an SVG file is general enough to allow for additional features beyond its core graphical functions. This flexibility, however, comes at the expense of security.
Unless there is a definite, demonstrable need, security professionals should consider banning SVG files in routine cases. When Google’s JS ban takes effect, malware authors will likely turn to SVG image-based attacks.