Connect with us

Hi, what are you looking for?


New Windows KB5009543, KB5009566 updates break L2TP VPN connections

windows 10 glass broken

Windows bug

Windows 10 users and administrators report problems making L2TP VPN connections after installing the recent Windows 10 KB5009543 and Windows 11 KB5009566 cumulative updates.

Yesterday, Microsoft released Windows updates to fix security vulnerabilities and bugs as part of the January 2022 Patch Tuesday.

These updates include KB5009566 for Windows 11 and KB5009543 for Windows 10 2004, 20H1, and 21H1.

Updates break L2TP connections

After installing yesterday’s updates, Windows users find their L2TP VPN connections broken when attempting to connect using the Windows VPN client.

When attempting to connect to a VPN device, they are shown an error stating, “Can’t connect to VPN. The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer,” as shown below.

Windows error when connecting to an LT2P VPN
Windows error when connecting to an LT2P VPN

The Event Log will also log entries with error code 789, stating that the connection to the VPN failed.

Windows event log for failed L2TP VPN connection
Windows event log for failed L2TP VPN connection

The bug is not affecting all VPN devices and seems only to be affecting users using the built-in Windows VPN client to make the connection.

A security researcher known as Ronny on Twitter told BleepingComputer that the bug affects their Ubiquiti Site-to-Site VPN connections for those using the Windows VPN client.

Many Windows admins also report on Reddit that the bug also affects connections to SonicWall, Cisco Meraki, and WatchGuard Firewalls, with the latter’s client also affected by the bug.

Advertisement. Scroll to continue reading.

With many users still working remotely, admins have been forced to remove the KB5009566 and KB5009543 updates, which immediately fixes the L2TP VPN connections on reboot.

Windows users can remove the KB5009566 and KB5009543 updates using the following commands from an Elevated Command Prompt.

Windows 10: wusa /uninstall /kb:5009543
Windows 11: wusa /uninstall /kb:5009566

However, as Microsoft bundles all security updates in a single Windows cumulative update, removing the update will remove all fixes for vulnerabilities patched during the January Patch Tuesday.

Therefore, Windows admins need to weigh the risks of unpatched vulnerabilities versus the disruption caused by the inability to connect to VPN connections.

It is not clear what caused the bug, but Microsoft’s January Patch Tuesday fixed numerous vulnerabilities in the Windows Internet Key Exchange (IKE) protocol (CVE-2022-21843, CVE-2022-21890, CVE-2022-21883, CVE-2022-21889, CVE-2022-21848, and CVE-2022-21849) and in the Windows Remote Access Connection Manager (CVE-2022-21914 and CVE-2022-21885) that could be causing the problems.

Unfortunately, there is no known fix or workaround for the L2TP VPN connection issues at this time.

BleepingComputer has reached out to Microsoft about the bug but has not received a reply yet.

Source link

Advertisement. Scroll to continue reading.
Click to comment

Leave a Reply


Top Stories

Although Bitcoin is struggling to form a bottom, altcoins are on a roll and the current price action could benefit UNI, XLM, THETA and...

Top Stories

Ethereum’s native token Ether (ETH) has declined by more than 35% against Bitcoin (BTC) since December 2021 with a potential to decline further in...

Top Stories

The company enables artists and collectors to create, purchase and resell NFTs via blockchain-enabled transactions. Source link


Interested in learning what’s next for the gaming industry? Join gaming executives to discuss emerging parts of the industry this October at GamesBeat Summit...

Top Stories

Bitcoin (BTC) made the most of weekend volatility on June 26 as a squeeze saw BTC/USD reach its highest in over a week. BTC/USD...


In a nutshell: Apple’s long-awaited mixed reality headset could be announced as soon as January, claims veteran supply chain analyst Ming-Chi Kuo. He says...


You May Also Like


Introductions get a lot of attention. I’ve explored the topic of how to write them even though as a reader, I always skip them....

Online Business Success

The internet is now our nervous system. We are constantly streaming and buying and watching and liking, our brains locked into the global information...

SEO Guide

There are all kinds of pictures of the world on the internet, but to find one of these specific pictures that you want to...

Online Business Success

You can think of link building in many ways. I like to call it tedious, painful, and a test of patience. It’s also necessary...