Bug

To exploit the vulnerability against an SMB Server, an unauthenticated attacker could send a specially crafted packet to a targeted SMBv3 Server. To exploit the vulnerability against an SMB Client, an unauthenticated attacker would need to configure a malicious SMBv3 Server and convince a user to connect to it.

We will update this advisory when updates are available. If you wish to be notified when this advisory is updated, we recommend that you register for the security notifications mailer to be alerted of content changes to this advisory. See Microsoft Technical Security Notifications.

We recently discovered that a Chrome update may have shipped with a bug that damages the file system on macOS machines with System Integrity Protection (SIP) disabled, including machines that do not support SIP. We've paused the release while we finalize a new update that addresses the problem.

Microsoft Windows Remote Desktop supports a feature called Network Level Authentication (NLA), which moves the authentication aspect of a remote session from the RDP layer to the network layer. The use of NLA is recommended to reduce the attack surface of systems exposed using the RDP protocol. In Windows a session can be locked, which presents the user with a screen that requires authentication to continue using the session. Session locking can happen over RDP in the same way that a local session can be locked. [...] Starting with Windows 10 1803 (released in April 2018) and Windows Server 2019, the handling of NLA-based RDP sessions has changed in a way that can cause unexpected behavior with respect to session locking. If a network anomaly triggers a temporary RDP disconnect, upon automatic reconnection the RDP session will be restored to an unlocked state, regardless of how the remote system was left. [...] At this point, an attacker can interrupt the network connectivity of the RDP client system. The RDP client software will automatically reconnect to the remote system once internet connectivity is restored. But because of this vulnerability, the reconnected RDP session is restored to a logged-in desktop rather than the login screen. This means that the remote system unlocks without requiring any credentials to be manually entered.