--- title: OS version description: OS version in Zero Trust. image: https://developers.cloudflare.com/zt-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/cloudflare-one/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) ### Tags [ Posture ](https://developers.cloudflare.com/search/?tags=Posture) # OS version The OS Version device posture attribute checks whether the version of a device's operating system matches, is greater than or lesser than the configured value. ## Prerequisites * Cloudflare One Client is [deployed](https://developers.cloudflare.com/cloudflare-one/team-and-resources/devices/cloudflare-one-client/deployment/) on the device. For a list of supported modes and operating systems, refer to [Cloudflare One Client Checks](https://developers.cloudflare.com/cloudflare-one/reusable-components/posture-checks/client-checks/). ## Enable the OS version check 1. In the [Cloudflare dashboard ↗](https://dash.cloudflare.com/), go to **Zero Trust** \> **Reusable components** \> **Posture checks**. 2. Go to **Cloudflare One Client checks** and select **Add a check**. 3. Select **OS version**. 4. Configure the **Operating system**, **Operator**, and **Version** fields to specify the [OS version](#determine-the-os-version) you want devices to match. Note The OS version must be specified as a valid [Semver ↗](https://semver.org/). For example, if your device is running OS version `1.2`, you must enter `1.2.0`. 5. (Optional) Configure additional OS-specific fields: * [ Windows ](#tab-panel-5163) * [ macOS ](#tab-panel-5164) * [ Linux ](#tab-panel-5165) * [ iOS ](#tab-panel-5166) To check that Windows devices have required security patches and features installed, include an Update Build Revision (UBR) number in the OS version check. * **Update Build Revision**: Enter the Windows UBR you want devices to match (for example, `3803`). The UBR is the fourth part of the full Windows version number (for example, in `10.0.19045.3803`, the UBR is `3803`). * **Rapid Security Response Version**: Enter the macOS [Rapid Security Response (RSR) ↗](https://support.apple.com/guide/deployment/rapid-security-responses-dep93ff7ea78/web) version you want devices to match (for example, `(a)`). Be sure to include the parenthesis around the letter. * **Distro name** and **Distro revision**: Enter the Linux distribution you want devices to match (for example, `ubuntu 22.04`). The distro version always matches with an equal-to operator (==) regardless of the **Operator** setting. * **Patch Version**: Enter the [patch version](#linux) of the kernel. For example, if the kernel is `6.50.0-1007-oem`, enter `1007`. * **Rapid Security Response Version**: Enter the iOS [Rapid Security Response (RSR) ↗](https://support.apple.com/guide/deployment/rapid-security-responses-dep93ff7ea78/web) version you want devices to match (for example, `(a)`). Be sure to include the parenthesis around the letter. 6. Select **Save**. Next, go to **Insights** \> **Logs** \> **Posture logs** and verify that the OS version check is returning the expected results. ## Determine the OS version Operating systems display version numbers in different ways. This section covers how to retrieve the version number in each OS, in a format matching what the OS version posture check expects. ### macOS 1. Open a terminal window. 2. Use the `defaults` command to check for the value of `SystemVersionStampAsString`. Terminal window ``` defaults read loginwindow SystemVersionStampAsString ``` ### Windows Windows version numbers consist of four parts: `Major.Minor.Build.UBR`. For example, `10.0.19045.3803` where: * `10.0` is the **Version** (Major.Minor) * `19045` is the **Build** number * `3803` is the **UBR** (Update Build Revision) To determine the Windows version on your device: 1. Open a PowerShell window. 2. Get the **Version** (Major.Minor.Build): Terminal window ``` (Get-CimInstance Win32_OperatingSystem).version ``` This returns the version in the format `Major.Minor.Build` (for example, `10.0.19045`). 3. Get the **UBR** (Update Build Revision): Terminal window ``` (Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion" -Name UBR).UBR ``` This returns the UBR value (for example, `3803`). ### Linux #### OS version The Linux OS version check reads the system kernel version. 1. Open a Terminal window. 2. Run the `uname -r` command to get the complete kernel version. For example, Terminal window ``` $ uname -r 5.14.0-25.el9.x86_64 ``` 3. **Version** is the first three numbers of the output in SemVer format (`5.14.0`). 4. **Patch Version** is the first number after the SemVer (`25`). #### Distro version The Cloudflare One Client reads **Distro name** and **Distro revision** from the `/etc/os-release` file. The name comes from the **ID** field, and the revision comes from the **VERSION\_ID** field. To determine the Linux distro version on your device: 1. Open a Terminal window. 2. Get the OS identification fields that contain `ID`: Terminal window ``` cat /etc/os-release | grep "ID" ``` 3. If the output of the above command contained `ID=ubuntu` and `VERSION_ID=22.04`, **Distro name** would be `ubuntu` and **Distro revision** would be `22.04`. The Cloudflare One Client will check these strings for an exact match. ### ChromeOS ChromeOS version numbers consist of [four parts ↗](https://www.chromium.org/developers/version-numbers/): `MAJOR.MINOR.BUILD.PATCH`. The OS version posture check returns `MAJOR.MINOR.BUILD`. To determine the ChromeOS version on your device: 1. Open Chrome browser and go to `chrome://system`. 2. Find the following values: | Property | OS version component | | ------------------------------------ | -------------------- | | CHROMEOS\_RELEASE\_CHROME\_MILESTONE | MAJOR | | CHROMEOS\_RELEASE\_BUILD\_NUMBER | MINOR | | CHROMEOS\_RELEASE\_BRANCH\_NUMBER | BUILD | 3. The OS version in Semver format is `MAJOR.MINOR.BUILD` (for example, `103.14816.131`). ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/cloudflare-one/","name":"Cloudflare One"}},{"@type":"ListItem","position":3,"item":{"@id":"/cloudflare-one/reusable-components/","name":"Reusable components"}},{"@type":"ListItem","position":4,"item":{"@id":"/cloudflare-one/reusable-components/posture-checks/","name":"Posture checks"}},{"@type":"ListItem","position":5,"item":{"@id":"/cloudflare-one/reusable-components/posture-checks/client-checks/","name":"Cloudflare One Client checks"}},{"@type":"ListItem","position":6,"item":{"@id":"/cloudflare-one/reusable-components/posture-checks/client-checks/os-version/","name":"OS version"}}]} ```