Microsoft has released a patch to fix a vulnerability in the SMBv3 protocol earlier than it had originally intended to after news of the bug accidentally leaked online.
The fix is available now as an update for Windows 10 (versions 1903 and 1909) and Windows Server 2019 (versions 1903 and 1909).
The update fixes the vulnerability, tracked as CVE-2020-0796, which exists in a protocol used for sharing files, printers and other resources on local networks and the internet called Server Message Block (SMB).
If exploited, the bug could allow an attacker to connect to remote systems that have the SMB service enabled and run malicious code with system privileges.
SMB Ghost flaw
As the result of a miscommunication between Microsoft and some antivirus makers, details about the bug leaked online before they were supposed to be released. The antivirus firms noted at the time that the bug could be weaponized by attackers to develop self-spreading SMB worms with similar capabilities to the WannaCry and NotPetya ransomware strains.
Microsoft had originally planned not to release a fix for the bug this month but the software giant was forced to do so once the news leaked online.
The recently released patch comes just in time as several researchers were able to develop basic proof-of-concept demos to show how the vulnerability could be used to cause crashes on vulnerable machines.
It is highly recommended that users running any of the affected versions of Windows 10 and Windows Server 2019 install the patch immediately but if you’re unable to do so, Microsoft has released a security advisory containing detailed mitigation advice.