Microsoft has patched a crucial Windows SMBv3 Client / Server remote code execution vulnerability that allows an attacker to remotely execute code.
The bug can be monitored as CVE-2020-0796 and only Windows 10 and Windows Server 1903 are affected. This was mistakenly leaked as part of the March 2020 Patch update on Tuesday.
SMBv3 RCE Flaw
The bug lies in the way that Microsoft Server Message Block 3.1.1 manages those requests. An attacker who exploits this vulnerability may execute code on the SMB Server or SMB Client target.
Now that Microsoft has fixed the vulnerability, server administrators are urged to introduce fixes to secure networks.
More than 48,000 vulnerable hosts have been found according to the search performed by Kryptos Logic. Kryptos Logic also added that a simple PoC was created.
An unauthenticated attacker may send a specially designed packet to a targeted SMBv3 server to exploit an SMB server vulnerability. An unauthenticated attacker will have to configure a malicious SMBv3 Server and persuade a user to connect to it in order to exploit the vulnerability against a SMB client, “says Microsoft paper.
Microsoft also claimed that the vulnerability had not yet been exploited and that the details had not been released publicly.
The versions affected
The bug affects versions of Windows 10 and 1903 of the Windows Server.
- Windows 10 Version 1903 for 32-bit Systems
- Windows 10 Version 1903 for x64-based Systems
- Windows 10 Version 1903 for ARM64-based Systems
- Windows Server, version 1903 (Server Core installation)
- Windows 10 Version 1909 for 32-bit Systems
- Windows 10 Version 1909 for x64-based Systems
- Windows 10 Version 1909 for ARM64-based Systems
- Windows Server, version 1909 (Server Core installation)