Browser Session Restore: Security Risks & How to Disable

TL;DR

Yes, disabling browser session restoration can improve cyber security. It reduces the risk of attackers gaining access to sensitive data if a user’s machine is compromised after they’ve logged in. However, it impacts usability – users will lose their open tabs and windows when closing the browser. Weigh these pros and cons carefully.

Why Disable Session Restoration?

Browser session restoration allows browsers to rebuild your previous browsing session (tabs, history, cookies) after a crash or restart. While convenient, this feature presents security risks:

• Malware Persistence: If malware infects a system after a user logs into legitimate sites (e.g., banking, email), it can potentially access the restored session and hijack those logins.
• Stolen Session Cookies: Stored session cookies are vulnerable. An attacker with access to the browser profile data could use these to impersonate the user.
• Physical Security Risks: If a device is left unattended, someone gaining physical access can easily resume the previous session and access sensitive information.

How to Disable Session Restoration – Step-by-Step

1. Google Chrome/Chromium-based Browsers (Edge, Brave etc.)
   • Open Chrome Settings: Click the three dots in the top right corner > Settings.
   • Navigate to Privacy and Security: Select Privacy and security from the left sidebar.
   • Cookies and other site data: Click on Cookies and other site data.
   • Disable ‘Continue where you left off’: Toggle this option off. This prevents Chrome from automatically restoring your previous session.
2. Mozilla Firefox
   • Open Firefox Settings: Click the three horizontal lines in the top right corner > Settings.
   • General Tab: Select General from the left sidebar.
   • Startup: Under ‘Firefox Startup’, choose either:
     • ‘Clear history when Firefox closes’: This is the most secure option, but also the most disruptive.
     • ‘Show my windows and tabs from last time’: Select this, then click Settings… next to it and uncheck ‘Restore previous session’.
3. Microsoft Edge (Legacy)
   • Open Edge Settings: Click the three dots in the top right corner > Settings.
   • On startup: Select ‘Start up’.
   • Choose what to open on start up: Select either:
     • ‘A blank page’: Most secure.
     • ‘Continue where you left off’: Toggle this option off.

Advanced Considerations

For greater control, consider these options:

• Browser Profile Management: Encourage users to create separate browser profiles for work and personal use. This isolates cookies and browsing data.
• Group Policy (Windows Domains): Administrators can enforce session restoration settings via Group Policy.

  reg add "HKLMSOFTWAREPoliciesGoogleChrome" /v RestoreSessionState /t REG_DWORD /d 0

  (This disables session restore in Chrome. Adjust the registry path for other Chromium browsers.)

• Regular Cookie Clearing: Implement a policy requiring users to regularly clear their browser cookies and cache.

Usability Trade-offs

Disabling session restoration means:

• Users will lose open tabs and windows when the browser is closed unexpectedly or restarted.
• They’ll need to manually re-open frequently used websites.

Communicate these changes clearly to users and provide training on alternative methods for managing browsing sessions (e.g., bookmarking, using a password manager).