CVE-2024-1563
📋 TL;DR
This vulnerability in Firefox Focus for iOS allows attackers to execute unauthorized JavaScript on top origin sites by exploiting a race condition when opening external URLs with custom Firefox schemes. It affects users running Firefox Focus for iOS versions below 122. The attack requires user interaction but can lead to script execution in privileged contexts.
💻 Affected Systems
- Firefox Focus for iOS
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could execute arbitrary JavaScript in the context of top origin sites, potentially leading to session hijacking, credential theft, or unauthorized actions on behalf of the user.
Likely Case
Limited script execution in specific contexts, potentially allowing attackers to read sensitive data or perform actions within the browser's security boundaries.
If Mitigated
With proper patching, no impact as the race condition is eliminated and URL handling is secured.
🎯 Exploit Status
Exploitation requires user interaction (clicking a malicious link) and precise timing due to race condition. No public exploit code has been disclosed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 122
Vendor Advisory: https://www.mozilla.org/security/advisories/mfsa2024-09/
Restart Required: Yes
Instructions:
1. Open the App Store on iOS device. 2. Search for Firefox Focus. 3. Tap Update to version 122 or later. 4. Restart the application after update completes.
🔧 Temporary Workarounds
Disable Firefox Focus
iosTemporarily disable or uninstall Firefox Focus until patched
Long press Firefox Focus app icon > Remove App
Use alternative browser
iosSwitch to standard Firefox for iOS or Safari until Firefox Focus is updated
🧯 If You Can't Patch
- Educate users to avoid clicking suspicious links while using Firefox Focus
- Implement network filtering to block known malicious domains that might host exploit code
🔍 How to Verify
Check if Vulnerable:
Open Firefox Focus > Settings > About. Check if version is below 122.Check Version:
Not applicable for iOS apps; check via app settingsVerify Fix Applied:
After updating, verify version is 122 or higher in Settings > About.📡 Detection & Monitoring
Log Indicators:
- Unusual JavaScript execution events in browser logs
- Multiple rapid URL opening attempts with custom schemes
Network Indicators:
- Requests to unusual domains following custom scheme URL activations
SIEM Query:
Not typically applicable for mobile browser vulnerabilities on personal devices