The update is related to the Countercept Agent’s FSBG components. The FSBG component is responsible for the core functionality (e.g. settings management and updates) of the Countercept Agent and does not affect the components responsible for telemetry collection or response.

Product Name: Countercept Agent for Linux – FSBG

Version: 1.0.921

Pilot Availability: 13/05/2025

General Availability: 20/05/2025

Predecessor: 1.0.918

Release Purpose:

• Generic Maintenance

Customer Action Required:

• N/A

Name Changes:

• No changes to file, process, or service names.

Files Updated:

• Most files are updated with this release.

New Features and Enhancements:

• N/A

Generic Maintenance:

• Fixes for issues identified during 1.0.920 Pilot.
• Fixed a possible deadlock issue in case of temporary update installation failures.
• The renewed corporate OpenPGP key is taken in use for the Critical security patching capability.
• Minor bug fixes and improvements.

OS Support:

• AMD64
  • AlmaLinux 8.4 – 9.x
  • Amazon Linux 2
  • CentOS 7, 8
  • Debian 10, 11, 12
  • Oracle Linux 7, 8, 9 (RHCK and UEK)
  • RHEL 7, 8, 9
  • Rocky Linux 8, 9
  • SUSE Linux Enterprise Server 12 SP3 – SP5
  • SUSE Linux Enterprise Server 15 SP1 – SP3
  • Ubuntu 18.04, 20.04, 22.04, 24.04
• ARMv8/AArch64
  • Debian 11, 12
  • Rocky 9
  • Ubuntu 22.04, 24.04

Please note that CentOS 6 and RHEL 6 are not supported. The Countercept Agent might break with this update, on endpoints where these operating systems are in use. WithSecure recommends upgrading these endpoints to the supported operating system versions, or switching clients to managed updates in collaboration with the WithSecure Engagement team.

This is a notification that the update to our Countercept Agent for Linux, containing general maintenance improvements for the Linux Agent’s FSBG component and released to Pilot group endpoints on the 5th of May 2025, has been cancelled.

Due to issues identified during the Pilot phase, the General Availability release for this FSBG component update has been cancelled and a new release will be prepared. We will advise on the release schedule for the new update shortly.

As always, please don’t hesitate to contact us if you have any questions.

The update is related to the Countercept Agent’s Ultralight Core component. Ultralight Core provides low-level functionality such as file hash calculation as part of the agent’s reporting of endpoint activity.

Product Name: Countercept Agent for Windows – Ultralight Core

Version: 2.1.20350

Pilot Availability: 07/05/2025

General Availability: 14/05/2025

Predecessor: 2.1.20210

Release Purpose:

• General maintenance

Customer Action Required:

• The Operating System should be Azure Code Signing (ACS) compliant to receive this update. See 
  
  https://community.withsecure.com/en/kb/articles/29714-changes-in-support-on-microsoft-windows-minimum-patch-level
  
  
           for more details.
  Any endpoints which are not ACS-compliant will continue to run the older version of the Ultralight Core (2.1.16183).

Name Changes:

New service will be registered with this release:

• wsulavprothoster_mdr

New process will be added with this release:

• fsulprothoster.exe

More details can be found at Changes to the Windows EPP Scanning Components – May 2025

Files Updated:

• CapricornScanner.exe
• fsulgk.sys
• install.exe
• uninstall.exe

New Features and Enhancements:

• N/A

General Maintenance:

• General maintenance of functionality not utilized by Countercept

OS Support:

• Windows 10, 11
• Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025

This is a notification that the update to our Windows agent’s Ultralight Core planned for the Pilot release on Tuesday the 29th April 2025, has been cancelled.

Due to possible effect to Countercept Agent caused by general maintenance of the functionality not utilized in the product, identified during the pre-Pilot phase, the Pilot release for the Ultralight Core has been cancelled and a new release will be prepared. We will advise on the release schedule for the new update.

The update is related to the Countercept Agent’s FSBG components. The FSBG component is responsible for the core functionality (e.g. settings management and updates) of the Countercept Agent and does not affect the components responsible for telemetry collection or response.

Product Name: Countercept Agent for Linux – FSBG

Version: 1.0.920

Pilot Availability: 05/05/2025

General Availability: 12/05/2025

Predecessor: 1.0.918

Release Purpose:

• Generic Maintenance

Customer Action Required:

• N/A

Name Changes:

• No changes to file, process, or service names.

Files Updated:

• Most files are updated with this release.

New Features and Enhancements:

• N/A

Generic Maintenance:

• Fixed a possible deadlock issue in case of temporary update installation failures.
• The renewed corporate OpenPGP key is taken in use for the Critical security patching capability.
• Minor bug fixes and improvements.

OS Support:

• AMD64
  • AlmaLinux 8.4 – 9.x
  • Amazon Linux 2
  • CentOS 7, 8
  • Debian 10, 11, 12
  • Oracle Linux 7, 8, 9 (RHCK and UEK)
  • RHEL 7, 8, 9
  • Rocky Linux 8, 9
  • SUSE Linux Enterprise Server 12 SP3 – SP5
  • SUSE Linux Enterprise Server 15 SP1 – SP3
  • Ubuntu 18.04, 20.04, 22.04, 24.04
• ARMv8/AArch64
  • Debian 11, 12
  • Rocky 9
  • Ubuntu 22.04, 24.04

Please note that CentOS 6 and RHEL 6 are not supported. The Countercept Agent might break with this update, on endpoints where these operating systems are in use. WithSecure recommends upgrading these endpoints to the supported operating system versions, or switching clients to managed updates in collaboration with the WithSecure Engagement team.

The update is related to the Countercept Agent’s Ultralight Core component. Ultralight Core provides low-level functionality such as file hash calculation as part of the agent’s reporting of endpoint activity.

Product Name: Countercept Agent for Windows – Ultralight Core

Version: 2.1.20350

Pilot Availability: 29/04/2025

General Availability: 05/05/2025

Predecessor: 2.1.20210

Release Purpose:

• General maintenance

Customer Action Required:

• The Operating System should be Azure Code Signing (ACS) compliant to receive this update. See 
  
  https://community.withsecure.com/en/kb/articles/29714-changes-in-support-on-microsoft-windows-minimum-patch-level
  
  
          for more details.
  Any endpoints which are not ACS-compliant will continue to run the older version of the Ultralight Core (2.1.16183).

Name Changes:

• No changes to file, process, or service names.

Files Updated:

• CapricornScanner.exe
• fsulgk.sys
• install.exe
• uninstall.exe

New Features and Enhancements:

• N/A

General Maintenance:

• General maintenance of functionality not utilized by Countercept

OS Support:

• Windows 10, 11
• Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025

The update is related to the Countercept Agent’s Sensor component. The Sensor component gathers data to be analyzed in the WithSecure backend to identify any malicious activity.

Product Name: Countercept Agent for Linux – Sensor Component

Version: 2025.1.198

Pilot Availability: 29/04/2025

General Availability: 06/05/2025

Predecessor: 2024.2.132

Release Purpose:

• New Features and Enhancements
• Generic Maintenance

Customer Action Required:

• N/A

Name Changes:

• No changes to file, process, or service names.

Files Updated:

• sensor

New Features and Enhancements:

• Performance improvements to file event gathering in Kernel 5.10 and newer.
• Detection improvements.
  • Changes to firewall rules are now monitored.
  • Shared library loadings are now monitored.
  • Shebang script information is now included in process details.
• SELinux file context is now handled by sensor’s installer.

Generic Maintenance:

• Fixes for issues identified during 2025.1.186 Pilot.
• Changes to sensor event handling and data storage to improve disk I/O, CPU and memory usage on high load systems.

OS Support:

• AMD64
  • AlmaLinux 8.4 – 9.x
  • Amazon Linux 2
  • CentOS 7, 8
  • Debian 10, 11, 12
  • Oracle Linux 7, 8, 9 (RHCK and UEK)
  • RHEL 7, 8, 9
  • Rocky Linux 8, 9
  • SUSE Linux Enterprise Server 12 SP3 – SP5
  • SUSE Linux Enterprise Server 15 SP1 – SP3
  • Ubuntu 18.04, 20.04, 22.04, 24.04
• ARMv8/AArch64
  • Debian 11, 12
  • Rocky 9
  • Ubuntu 22.04, 24.04

Please note that CentOS 6 and RHEL 6 are not supported. The Countercept Agent will break with this update, on endpoints where these operating systems are in use. WithSecure recommends upgrading these endpoints to the supported versions of the operating system, or switching clients to managed updates in collaboration with the WithSecure Engagement team.

This is a notification that an update to our Windows agent’s sensor component will be issued shortly. This release replaces the previous Windows agent’s sensor update released to Pilot group endpoints on Wednesday, the 16th of April 2025, and never proceeded to General Availability due to an issue identified during the Pilot phase.

The Sensor component gathers data to be analyzed in the WithSecure backend to identify any malicious activity. 

Product Name: Countercept Agent for Windows – Sensor Component

Version: 2025.1.89

Pilot Availability: 24/04/2025

General Availability: 05/05/2025

Predecessor: 2024.2.31

Release Purpose:

• New Features and Enhancements
• Generic maintenance

Customer Action Required:

• The Operating System should be Azure Code Signing (ACS) compliant to receive this update. See 
  
  https://community.withsecure.com/en/kb/articles/29714-changes-in-support-on-microsoft-windows-minimum-patch-level
  
  
      for more details.
  Any endpoints which are not ACS-compliant will continue to run the previous production version of the sensor (2023.1.75).

Name Changes :

• No changes to file, process, or service names.

Files Updated :

• fsatp.sys
• fsatpl.exe
• fsatpn.exe
• install.exe
• sensor_control.exe

New Features and Enhancements:

• Detection improvements
• Interoperability improvements

General Maintenance:

• Fix for large amount of unnecessary events being sent by the 2025.1.85 sensor. This fix was omitted from
  2025.1.86 release due to sensor malfunction being prioritized.
• Crash fixes

OS Support:

• Windows 10, 11
• Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025

Please note that Windows 7 and Windows Server 2008 (R2) are not supported. On endpoints where these operating systems are in use, the Countercept agent will not be updated, and the previous sensor version (2024.2.31) will continue to run. New Countercept agent installations to these operating systems are now impossible.