“We have discovered through our analysis that some components of the malware have been signed by certificates that allow software to appear as if it was produced by Microsoft,” Microsoft Security Response Center’s Jonathan Ness wrote in a blog post.
Microsoft is also warning that the same techniques could be leveraged by less sophisticated attackers to conduct more widespread attacks.
In response to the discovery, Microsoft released a security advisory detailing steps that organizations should take in order block software signed by the unauthorized certificates, and also released an update to automatically protect customers. Also as part of its response effort, Microsoft said its Terminal Server Licensing Service no longer issues certificates that allow code to be signed."
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