An actively exploited Microsoft 0-day flaw still doesn’t have a patch

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Researchers warned last weekend that a flaw in Microsoft's Support Diagnostic Tool could be exploited using malicious Word documents to remotely take control of target devices. Microsoft released guidance on Monday, including temporary defense measures. By Tuesday, the United States Cybersecurity and Infrastructure Security Agency had warned that “a remote, unauthenticated attacker could exploit this vulnerability,” known as Follina, “to take control of an affected system.” But Microsoft would not say when or whether a patch is coming for the vulnerability, even though the company acknowledged that the flaw was being actively exploited by attackers in the wild. And the company still had no comment about the possibility of a patch when asked by WIRED.

The Follina vulnerability in a Windows support tool can be easily exploited by a specially crafted Word document. The lure is outfitted with a remote template that can retrieve a malicious HTML file and ultimately allow an attacker to execute Powershell commands within Windows. Researchers note that they would describe the bug as a “zero-day,” or previously unknown vulnerability, but Microsoft has not classified it as such.