Microsoft admits to signing rootkit malware in supply-chain fiasco

Tech giant Microsoft has now confirmed signing a malicious driver being distributed within gaming environments.

According to Bleeping Computers, this driver, called “Netfilter,” is a rootkit that was observed communicating with Chinese command-and-control (C2) IPs.

G Data malware analyst Karsten Hahn first took notice of this event last week and was joined by the wider infosec community in tracing and analyzing the malicious drivers bearing the seal of Microsoft.

This incident has once again exposed threats to software supply-chain security, except this time it stemmed from a weakness in Microsoft’s code-signing process.

Microsoft said it is actively investigating this incident, although thus far, there is no evidence that stolen code-signing certificates were used.

The mishap seems to have resulted from the threat actor following Microsoft’s process to submit the malicious Netfilter drivers and managing to acquire the Microsoft-signed binary in a legitimate manner.

“Microsoft is investigating a malicious actor distributing malicious drivers within gaming environments,” the company was quoted as saying by the website.

“We have suspended the account and reviewed their submissions for additional signs of malware,” said Microsoft yesterday.

According to Microsoft, the threat actor has mainly targeted the gaming sector specifically in China with these malicious drivers and there is no indication of enterprise environments having been affected so far.