Enabling Strict Site Isolation in Google Chrome: A Comprehensive Guide

In the ever-evolving landscape of cybersecurity, protecting your browser from vulnerabilities like Spectre and Meltdown is paramount. One effective method is enabling strict site isolation in Google Chrome. This article delves into how to enable the SitePerProcess flag, achieving robust security through Chrome policy configurations.

Understanding Site Isolation and its Importance

Site isolation is a security feature that isolates websites into separate processes, preventing malicious scripts from one site from accessing data from another. This is particularly crucial in mitigating speculative execution side-channel attacks like Spectre and Meltdown. By implementing strict site isolation, you significantly enhance your browser's security posture.

The Challenge: Configuring Chrome Flags

Enabling Chrome flags, such as SitePerProcess, can sometimes be tricky. While chrome://flags provides a way to "force" enable features, it's not the recommended approach for enterprise deployments or ensuring persistent settings. Google advises using Chrome policies for deploying the site isolation feature for better control and reliability.

The Recommended Solution: Configuration Profiles

The most reliable method to enable strict site isolation is through configuration profiles. Here’s how you can achieve this:

1. Create a Configuration Profile: Use a tool like Jamf Pro to create a new configuration profile.
2. Custom Settings Payload: Within the configuration profile, add a custom settings payload specifically for Google Chrome.
3. Upload the Chrome plist: Upload a .plist file containing the necessary configuration. Here’s an example of what the .plist file should look like:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>SitePerProcess</key>
    <true/>
</dict>
</plist>

4. Scope the Profile: Deploy the configuration profile to your target machines.

Verifying the Configuration

After deploying the configuration profile, it's crucial to verify that the SitePerProcess flag has been successfully enabled. Do not rely on chrome://flags for verification. Instead, follow these steps:

1. Navigate to chrome://policy: This page displays all the active Chrome policies on the browser.
2. Check for SitePerProcess: Look for the SitePerProcess policy and confirm that its status is "Enabled."
3. Use Google's Test Page: Visit Google's support page and follow the steps under "Verify site isolation" to test if strict site isolation is working correctly.

Troubleshooting Common Issues

• Settings Not Reflected in Chrome UI: The Chrome UI might not accurately reflect managed settings. Always verify using chrome://policy and Google's test page.
• Configuration Profile Not Working: Ensure the configuration profile is correctly scoped and applied to the target machines. Double-check the syntax of your .plist file.
• Conflicting Settings: Remove any conflicting settings or policies that might be overriding the SitePerProcess flag.

Additional Tips and Considerations

• Testing: Before deploying the configuration profile to your entire environment, test it on a few machines to ensure it works as expected.
• Documentation: Refer to the official Chromium policy list for detailed information on the SitePerProcess policy.
• Jamf Pro: Utilizing Jamf Pro simplifies the deployment and management of configuration profiles across your Apple devices.

By following these steps, you can effectively enable strict site isolation in Google Chrome, enhancing your organization's security and protecting against potential threats.