In our blog from yesterday, we described how Exploit-MSDirectShow.b has been widely deployed on hijacked websites in China, targeting Internet Explorer users. When a victim browses one of these sites, malware is downloaded to the computer. To better understand the current impact of these attacks, we have monitored the prevalence of its downloaded malware through Artemis.

Since yesterday, our Artemis technology has detected new malware installed by Exploit-MSDirectShow.b that was targeted to certain geographical regions of the world.

In China, a new sample variant was queried by Artemis more than 180 times at more than 70 unique IP addresses (ISP, not end point) over a 24-hour period. This is represented by the many red dots in the following figure:

This particular sample was first seen only in mainland China, but we soon saw Artemis queries from Korea, Japan, Australia, Singapore, Taiwan, and the United States in very small numbers. As we know, the web has no boundaries and the potential risks of the DirectShow zero-day vulnerability is not limited to specific languages or regions. We will closely monitor this trend.

This sample is already heuristically detected in the DATs and Artemis. After our analysis, it has now been classified as Downloader-BRT Trojan.