RemoteApp Slow after Windows10 1803 update on Server 2012 R2

As the title suggests, after updating Windows 10 computers to 1803, users have reported slow RemoteApp sessions.

You can try disabling Remote FX, but user reports suggest this causes further issues.

The easiest fix is to copy mstsc.exe and mstscax.dll from a 1709 build and replace the files on 1803. We have confirmed this works.

KB4103727 Breaks RDP/Remote Desktop Gateway

This morning we awoke to screams from users not being able to login to our remote desktop servers.

KB4103727 has been released which switches a flag to protect against the CredSSP attack.

The quickest way to fix this to get your users working is to patch your domain controller with the May updates and use group policy to push out a change

You can manually add this to the registry for desktop clients

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\CredSSP\Parameters] "AllowEncryptionOracle"=dword:00000002

or via command line

reg add "HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\CredSSP\Parameters" /f /v AllowEncryptionOracle /t REG_DWORD /d 2

To fix this problem, the May updates need to be installed on all servers and workstations.

More information:

 

Patch Tuesday: CVE-2017-11826 Microsoft Office

There is an in-the-wild exploit for Microsoft Office. A patch has been released. This exploit has turned up on Virtus Total today.

A remote code execution vulnerability exists in Microsoft Office software when the software fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the current user. If the current user is logged on with administrative user rights, an attacker could take control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

Exploitation of the vulnerability requires that a user open a specially crafted file with an affected version of Microsoft Office software. In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and convincing the user to open the file. In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) containing a specially crafted file designed to exploit the vulnerability. An attacker would have no way to force users to visit the website. Instead, an attacker would have to convince users to click a link, typically by way of an enticement in an email or instant message, and then convince them to open the specially crafted file.