This Week In Security: Bad Signs From Microsoft, An Epyc VM Escape

Code signing is the silver bullet that will save us from malware, right? Not so much, particularly when vendors can be convinced to sign malicious code. Researchers at G DATA got a hit on a Windows kernel driver, indicating it might be malicious. That seemed strange, since the driver was properly signed by Microsoft. Upon further investigation, it became clear that this really was malware. The file was reported to Microsoft, the signature revoked, and the malware added to the Windows Defender definitions.

The official response from Microsoft is odd. They start off by assuring everyone that their driver signing process wasn’t actually compromised, like you would. The next part is weird. Talking about the people behind the malware: “The actor’s goal is to use the driver to spoof their geo-location to cheat the system and play from anywhere. The malware enables them to gain an advantage in games and possibly exploit other players by compromising their accounts through common tools like keyloggers.” This doesn’t seem to really match the observed behavior of the malware — it seemed to be decoding SSL connections and sending the data to the C&C server. We’ll update you if we hear anything more on this one.
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This Week In Security: Schemeflood, Modern Wardialing, And More!

There’s been yet another technique discovered to fingerprint users, and this one can even work in the Tor browser. Scheme flooding works by making calls to application URLs, something like steam://browsemedia. If your machine supports the requested custom URL, a pop-up is displayed, asking permission to launch the external application. That pop-up can be detected by JavaScript in the browser. Detect enough apps, and you can build a reasonable fingerprint of the system the test is run on. Unlike some previous fingerprinting techniques, this one isn’t browser dependent — it will theoretically give the same results for any browser. This means even the Tor browser, or any browser being used over the Tor network, can give your potentially unique set of installed programs away.

Now for the good news. The Chrome devs are already working on this issue, and in fact, Chrome on my Linux desktop didn’t respond to the probes in a useful way. Feel free to check out the demo, and see if the results are accurate. And as for Tor, you really should be running that on a dedicated system or in a VM if you really need to stay anonymous. And disable JavaScript if you don’t want the Internet to run code on your computer.
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