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    Prisma Browser Extension Support for Firefox

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    Prisma Browser Extension Support for Firefox

    Prisma Browser Extension extends last-mile security controls to the Mozilla Firefox browser, so administrators can apply consistent policy across Firefox and Chromium-based browsers.
    Where Can I Use This?What Do I Need?
    • Strata Cloud Manager
    • Prisma Browser standalone
    • Prisma Access with Prisma Browser bundle license or Prisma Browser standalone license
    • Superuser or Prisma Browser role
    The Prisma Browser Extension for Firefox brings the Prisma Browser Extension to Mozilla Firefox, extending last-mile visibility and enforcement beyond Chromium-based browsers. Administrators install the extension on Firefox and apply the same policy rules used for other supported browsers, so protection follows users regardless of which browser they choose.

    Install the Prisma Browser Extension on Firefox

    Install the Prisma Browser Extension for Firefox from the Prisma Browser onboarding page in Strata Cloud Manager:
    1. From Strata Cloud Manager, open the Prisma Browser setup and select Step 5: Download and distribute.
    2. Expand Deploy Prisma Browser Extension.
    3. Under Generate Manual Configuration, select the Firefox browser tab.
    4. Select the IdP for Auto-login and the Device management type for your deployment.
    5. Click Generate to produce the Firefox configuration.
    6. Distribute the generated configuration to end users through your standard browser deployment or mobile device management (MDM) workflow.

    Controls That Are Not Available on Firefox

    The Prisma Browser Extension and its Firefox version share policy rules. However, some controls within the policy rules operate differently on Firefox, or are not yet available, due to differences in how Firefox exposes browser capabilities to extensions.
    The following controls are not available on Firefox:
    • Allowed and Blocked Extensions - Firefox does not support the control that governs which browser extensions users can install.
    • Popups Control - Firefox does not support the control that governs browser popups.
    • Notification Control - Firefox does not support the control that governs browser notifications.

    File Download Behavior on Firefox

    The File Download control is supported on Firefox, with limitations in how downloads are enforced. On Chromium-based browsers, the Prisma Browser Extension holds a download before it is written to the device and blocks it if a rule matches. Firefox does not provide an equivalent pre-write download hold, so the Prisma Browser Extension decides when the download starts and either allows it or cancels it. As a result, hard blocking is not always possible: in some cases a file briefly reaches the device and is then deleted.

    How Enforcement Differs

    • No pre-write hold - Firefox always starts the download. The Prisma Browser Extension cancels the download when a rule matches, and removes the file if it has already reached the device.
    • File content scanning (malware and Data Leak Prevention) - The file content is not scanned on Firefox. A rule that depends on content inspection does not apply, and the download is kept.
    • Renamed file - A file renamed to a different extension (for example, an .exe saved as .txt) is not detected on Firefox, because the file's contents are not read.
    • File hash - A rule that matches on file hash does not block the download on Firefox, because the file's contents are not read.
    • File size - A rule that matches on file size detects and deletes the file after the download completes, rather than blocking it beforehand. If the file size never becomes known, the rule does not apply and the download is kept.
    • MIP label - A rule that matches on a MIP label cannot read the label on Firefox. The condition is treated as matched, and the rule's other conditions still apply.
    • Silent blocks - On a direct-URL download or a tab with no page content, the block is still enforced, but no notification is shown to the user.

    Guarantee a Hard Block for Downloads

    Because Firefox does not generate an event that lets the Prisma Browser Extension hold a download before it is written, hard blocking is not always possible. In some cases, a file reaches the device briefly before being deleted.
    To ensure a hard block—where a blocked file never reaches the device—configure download blocking using the Firefox browser deployment policy. Firefox provides a built-in enterprise policy for content analysis that blocks downloads before any file content is written, which can be applied to all downloads or scoped to specific sites.
    To ensure a hard block for downloads on Firefox, follow the Block Downloads in Firefox deployment guide. It provides step-by-step configuration, including the policy file, supported platforms, minimum Firefox version, and rollout options (MDM, Group Policy, or the extension's existing managed configuration).
    For more information on configuring download and data protection controls, refer to Configure Data Leak Prevention. For more information on the Prisma Browser Extension, refer to The Prisma Browser Extension.

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