Viscosity version 1.10.3 has been released for both macOS and Windows! This version adds several commonly requested features, including VPN connection sorting, and separately prompting for two-factor credentials that normally form part of the password. Updates to OpenVPN and OpenSSL are also included, along with many small bug fixes and enhancements.

This update adds a new static-challenge-password command to allow Viscosity to separately prompt for a two-factor credential (such as a one-time password or PIN) and append this credential to the password sent to the server. While we encourage VPN administrators to adopt OpenVPN's static/dynamic challenge support instead (such as documented in the Two-Factor Authentication Setup Guides), we understand there are many legacy setups out there still using this approach. This will allow for a much smoother experience, including enabling username and passwords to be saved without affecting the two-factor prompt.

Another common feature request we've added is the ability to quickly sort VPN connections and folders to make organising and managing them faster. Several sorting options are available, including sorting all connections and folders, just selected items, or just items in a folder. Simply right-click (or control-click) on the items to be sorted and select the appropriate Sort menu option.

On the Windows side, Viscosity will now automatically detect and repair certain issues with a VPN connection's virtual network interface that could cause a connection attempt to fail. When this occurred, Viscosity would disconnect the connection shortly after starting, with an error message in the log indicating the network adapter could not be found. We discovered that in some instances severely out-of-date third-party network filters attached to the VPN interface could cause it to fail. Viscosity will now detect when this is the case and repair the problem.

On macOS, an issue with the Viscosity helper has been resolved that could on rare occasions cause the helper to crash when sleeping the computer with an active VPN connection. This largely only occurred for Apple Silicon users with TAP connections, however in very rare instances it could also occur on Intel Macs, requiring Viscosity to be re-launched on wake.

Finally, this version also updates OpenVPN 2.5 to version 2.5.7, OpenVPN 2.4 to version 2.4.12, and OpenSSL to version 1.1.1o. These updates include a number of small bug fixes and improvements.

Version 1.10.3 Mac Release Notes:

Version 1.10.3 Windows Release Notes:

The 1.10.3 update can be automatically installed from inside Viscosity, or downloaded and manually installed. For support with this version please visit our support section.

Viscosity version 1.10.2 is now available for both macOS and Windows! This update introduces Dark Mode support for the Windows version, a security-related OpenSSL update for both macOS and Windows versions, along with several small bug fixes and enhancements.

The updated version of OpenSSL addresses a potential security issue with OpenSSL's certificate parsing that could result in a denial-of-service attack. This does not affect the security of OpenVPN connections. However, it could potentially allow a malicious server or man-in-the-middle attacker to stall a VPN connection attempt with an infinite loop, resulting in high CPU usage until the connection attempt is disconnected.

The Windows version also introduces preliminary Dark Mode support. If Windows is set to use Dark Mode, Viscosity will now automatically render its interface using the appropriate dark theme colors. This is still a work in progress, however Dark Mode fans should be less blinded when opening Viscosity's interface with this update.

The macOS version also fixes a number of small IPv6 related issues, including not correctly displaying the IPv6 address assigned to a VPN connection in the menu or Details window.

Version 1.10.2 Mac Release Notes:

Version 1.10.2 Windows Release Notes:

The 1.10.2 update can be automatically installed from inside Viscosity, or downloaded and manually installed. For support with this version please visit our support section.

Viscosity version 1.10.1 is now available for both macOS and Windows! This update is primarily a small maintenance release with bug fixes and minor enhancements to keep Viscosity running smoothly.

In particular, the Mac version is now able to detect and workaround an issue that caused Viscosity to hang in the background when trying to update old versions of its helper tool on macOS 12. It is no longer necessary to manually remove old versions of the helper on macOS 12 in these instances.

The Windows version also resolves a similar issue that could cause VPN connections to fail if Windows had been upgraded from Windows 10 to Windows 11 without the driver being manually updated.

Version 1.10.1 Mac Release Notes:

Version 1.10.1 Windows Release Notes:

The 1.10.1 update can be automatically installed from inside Viscosity, or downloaded and manually installed. For support with this version please visit our support section.

Viscosity 1.10 is now available for both macOS and Windows! This is a big update, with OpenVPN 2.5 support, support for both macOS 12 and Windows 11, support for SSO and SAML authentication, and lots of other new features and improvements.

OpenVPN 2.5 brings several new features to VPN connections, including support for the ChaCha20-Poly1305 cipher, TLS 1.3 support, improved session token management, and many other networking improvements. OpenVPN 2.5 is backwards compatible with servers running older versions of OpenVPN, however Viscosity still includes OpenVPN 2.4 which can be enabled at any time under Preferences->Advanced.

This release also adds support for the latest macOS and Windows operating systems. macOS 12 (Monterey), expected to be available shortly, is now supported. Windows 11, just recently released, is now fully supported as well.

Please note that while macOS 12 is supported, iCloud Private Relay beta (available in macOS 12) has several known incompatibilities with common VPN setups. We hope to have improved compatibility with Private Relay in a future update.

Viscosity 1.10 also introduces support for SSO and SAML authentication, allowing OpenVPN setups to better integrate into existing enterprise authentication systems. For those with custom OpenVPN server setups, we expect to have setup guides on how to configure SSO/SAML server-side in our knowledge base soon.

Viscosity’s Import from Server feature has also been overhauled, and now supports a number of new features, including web-based authentication (including SSO/SAML), automatic detection and TOTP two-factor enrollment, and support for OpenVPN Cloud.

Also included are many additional small improvements and bug fixes. More details can be found in the release notes below.

Finally, this update requires macOS 10.15 or later on Mac, and Windows 10 or later on Windows. macOS 10.13 and 10.14, and Windows 7 and 8.1, are no longer supported. These older OS versions are either no longer receiving security updates, or require the use of deprecated OS APIs that make supporting newer OS versions significantly more difficult. Older Viscosity releases that will run on these versions can still be found at the Legacy Downloads page.

Version 1.10 Mac Release Notes:

Version 1.10 Windows Release Notes:

The 1.10 update can be automatically installed from inside Viscosity, or downloaded and manually installed. For support with this version please visit our support section.

Viscosity version 1.9.4 is now available for both macOS and Windows! This update is a security release and includes an important security fix for the macOS version, OpenSSL updates for both platforms, and a number of small bug fixes.

On the macOS side, a privilege escalation vulnerability has been identified that could potentially allow a local user to gain elevated privileges with a maliciously crafted update bundle. Local machine access is required, it cannot be exploited remotely, and it does not affect the security of VPN connections. However, as it potentially allows a standard user to gain admin (root) permissions, we've classified it as a high severity issue. We strongly encourage all macOS users to update to version 1.9.4 as soon as possible, particularly those in multi-user or enterprise environments. Special thanks to AfkVkas for taking a look at Viscosity and identifying this attack chain.

While the Windows version is not affected by this issue, we've taken the opportunity to perform some additional hardening of the service in this update. Both versions also include an updated version of OpenSSL and several small bug fixes.

Version 1.9.4 Mac Release Notes:

Version 1.9.4 Windows Release Notes:

The 1.9.4 update can be automatically installed from inside Viscosity, or downloaded and manually installed. For support with this version please visit our support section.

Viscosity version 1.9.3 is now available for both macOS and Windows! This update includes a number of improvements, including refined support for Apple Silicon (M1) Macs, updated versions of both OpenVPN and OpenSSL, and a number of small bug fixes.

In particular, the Mac version has been updated to automatically detect common DNS misconfigurations and add a warning where appropriate. Problems such as unreachable servers, DNS servers routed through the wrong network interface, use of reserved DNS domains, conflicting DNS domains, and so forth, will be now identified and additional information added to the connection log. We anticipate this should greatly simplify troubleshooting DNS problems for users and administrators unfamiliar with macOS's DNS resolver system.

This version also updates OpenVPN to version 2.4.11 for both Mac and Windows. While this OpenVPN update addresses a potentially serious security issue, it only affects OpenVPN servers. Viscosity clients are unaffected.

Finally, this version also updates OpenSSL to version 1.1.1k for both platforms.

As a follow-up, we're pleased to report that Apple have confirmed that they've resolved the underlying problem (that could cause macOS updates to stall) that necessitated the previous 1.9.2 release of Viscosity with a workaround. This has been resolved in the recent macOS 11.3 update. While we'll leave Viscosity's workaround in place for the foreseeable future (out of an abundance of caution), updating to macOS 11.3 and onwards should always go smoothly, even if an older version of Viscosity is being used.

Version 1.9.3 Mac Release Notes:

Version 1.9.3 Windows Release Notes:

The 1.9.3 update can be automatically installed from inside Viscosity, or downloaded and manually installed. For support with this version please visit our support section.

Viscosity version 1.9.2 is now available for Windows! This update is primarily a maintenance release with bug fixes and small enhancements.

This release focuses on improving support for High DPI Scaling and multi-monitor setups on Windows. In particular, Viscosity will now fully handle setups where the DPI scaling varies from monitor to monitor, and support for High DPI user interface elements has been improved. To allow for DPI Scaling improvements, Viscosity now also requires .NET 4.8 or later.

Finally, we’ve also identified and fixed an issue that could cause a DNS domain to fail to be correctly used as a DNS suffix when using the legacy OpenVPN TAP Adapter.

Version 1.9.2 Windows Release Notes:

The 1.9.2 update can be automatically installed from inside Viscosity, or downloaded and manually installed. For support with this version please visit our support section.

Viscosity version 1.9.2 is now available for macOS! This is a small update designed to address a single issue related to system updates on macOS 11 (Big Sur). Version 1.9.1 remains the latest Windows version.

We've identified a situation where Viscosity could inadvertently trigger a bug in the macOS update process when updating macOS 11 from version 11.0 or 11.1 to version 11.2.x. This bug can result in the update process stalling at a black screen (with an Apple logo and progress bar) for affected installs.

While this appears to be a bug in the macOS update process, and not directly with Viscosity itself, as it is highly disruptive to those impacted we've elected to push out this update with a workaround in Viscosity to avoid it. If you're running macOS 11 and haven't yet updated it to the latest version, we strongly encourage you to update Viscosity to version 1.9.2 before proceeding.

It's only possible for this bug to be triggered in a small number of instances, and so the vast majority of Viscosity users will not be impacted. Users not updating between the above versions of macOS shouldn't be affected. Users connecting TUN connections are not affected. Users connecting TAP connections may be affected depending on the VPN configuration and cached network settings.

If you've already tried updating macOS 11 and the update has stalled, you can boot your computer into Safe Mode (please note that the process differs between Intel and Apple Silicon Macs) and re-run the update from there. It may be necessary to download and run the full macOS 11 installer from the App Store to complete the update. It is not necessary to erase your computer or restore from Time Machine. If you're unable to boot your computer into Safe Mode, then the cause for the stalled update is unlikely to be related to Viscosity.

Special thanks to Tobias Punke for initially reporting this issue.

Version 1.9.2 Mac Release Notes:

The 1.9.2 update can be automatically installed from inside Viscosity, or downloaded and manually installed. For support with this version please visit our support section.

Viscosity version 1.9.1 is now available for both macOS and Windows! This update is primarily a maintenance release, and includes improved support for macOS 11, improved compatibility with OpenVPN configurations, updated OpenVPN and OpenSSL versions, and a number of small bug fixes and improvements for both platforms.

In particular, on the Mac side there have been a number of behind-the-scenes fixes and enhancements to improve compatibility and performance with macOS 11 (Big Sur). Support for Macs with Apple Silicon (M1) processors has also been improved.

Both the Mac and Windows versions will now also correctly handle the use of data-ciphers and related commands by automatically re-mapping them to the equivalent OpenVPN 2.4 commands.

Finally, this version also updates OpenVPN to version 2.4.10, and OpenSSL to version 1.1.1i, for both platforms.

Version 1.9.1 Mac Release Notes:

Version 1.9.1 Windows Release Notes:

The 1.9.1 update can be automatically installed from inside Viscosity, or downloaded and manually installed. For support with this version please visit our support section.

Viscosity 1.9 is now available for both macOS and Windows! This is one of our biggest updates yet, with significant changes under-the-hood and many new features.

One of the most anticipated additions in version 1.9 is support for macOS 11 (Big Sur). Viscosity now supports and integrates with macOS 11, and all of Viscosity's existing functionality is fully supported (including TAP support - more on that below).

We've also ported Viscosity to have complete native support for the upcoming Apple Silicon (ARM) Macs. Viscosity and your VPN connections will run at native speed to take full advantage of the new processor architecture and power savings.

Version 1.9 also introduces driverless TAP (bridged) connection support on macOS. This is something we are particularly enthusiastic about: if you use TAP (bridged) OpenVPN connections you'll no longer need to manually approve a kernel extension to load before you're able to connect. This will also make deployment much easier in enterprise environments. And best of all, our approach fully supports macOS 11.

On the Windows side, version 1.9 introduces a brand-new VPN network adapter driver for Windows 10 2004 and later. This driver has been written from the ground up for modern Windows 10 machines. It does away with using legacy system frameworks to help optimise performance and lower resource usage. It also includes privacy improvements, such as generating a random ethernet (MAC) address each time you connect, as well as better support for custom MTU values and custom MAC addresses (using the lladdr command) for TAP connections.

A common request from Viscosity power users is for more powerful scripting support, and we're pleased to be able to say we've done just that. Both AppleScript scripts on macOS, and Batch scripts on Windows now have access to connection details, making it easier to write scripts that respond to different network changes. This also makes it easier to share scripts between connections, or even different users.

It's now also possible for Before-Connect scripts to return username and password credentials, making it easy to craft custom authentication prompts, integrate with custom authentication systems, or manually handle credential storage.

The Windows version also updates the DNS system to improve the reliability of Network Location Awareness (NLA) when connected to a VPN on newer versions of Windows 10. This should resolve an issue where certain applications, such as Microsoft Office, may be unable to use network services while connected. Also addressed in the Windows update is a low-severity security vulnerability that could allow certain libraries to be side-loaded from the same directory when the Windows installer is run. Thank you to Vladimir Dubrovin for reporting this.

It's also important to note that this update drops support for OpenVPN 2.3. Viscosity will still be able to connect to servers running OpenVPN 2.3 or older versions, however OpenVPN 2.4 will now be used client-side. For the vast majority of users no migration changes are needed and connections will automatically work. However if you've updated and can no longer connect please refer to our migration guide.

Finally, version 1.9 also includes many more small improvements and bug fixes. For further information please refer to the release notes below.

Version 1.9 Mac Release Notes:

Version 1.9 Windows Release Notes:

The 1.9 update can be automatically installed from inside Viscosity, or downloaded and manually installed. For support with this version please visit our support section.