CVE-2020-3864
📋 TL;DR
This CVE describes a logic issue in Apple's DOM implementation where a DOM object context may not have had a unique security origin. This could allow malicious websites to bypass same-origin policy protections and potentially access sensitive data from other websites. Affected users include those running vulnerable versions of iCloud for Windows, iTunes for Windows, Safari, iOS, iPadOS, and tvOS.
💻 Affected Systems
- iCloud for Windows
- iTunes for Windows
- Safari
- iOS
- iPadOS
- tvOS
📦 What is this software?
Icloud by Apple
Icloud by Apple
Ipados by Apple
Itunes by Apple
Safari by Apple
Tvos by Apple
⚠️ Risk & Real-World Impact
Worst Case
Complete bypass of same-origin policy allowing malicious websites to steal sensitive data (cookies, session tokens, personal information) from other websites the user has open.
Likely Case
Targeted attacks against users visiting malicious websites while having other sensitive sites open, potentially leading to session hijacking or data theft.
If Mitigated
Limited impact with proper web security controls, browser sandboxing, and updated software.
🎯 Exploit Status
Exploitation requires user interaction (visiting malicious website) but no authentication needed. The vulnerability is in the browser/DOM implementation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: iCloud for Windows 7.17+, iTunes 12.10.4+ for Windows, iCloud for Windows 10.9.2+, tvOS 13.3.1+, Safari 13.0.5+, iOS 13.3.1+, iPadOS 13.3.1+
Vendor Advisory: https://support.apple.com/en-us/HT210918
Restart Required: Yes
Instructions:
1. Open affected application (Safari, iTunes, iCloud, or device Settings). 2. Check for updates. 3. Install available updates. 4. Restart the application or device as prompted.
🔧 Temporary Workarounds
Disable JavaScript
allTemporarily disable JavaScript in affected browsers to prevent exploitation.
Use Alternative Browser
allUse a different, updated browser until Apple software can be patched.
🧯 If You Can't Patch
- Implement web application firewall rules to block known malicious domains
- Use browser extensions that enforce strict same-origin policy
🔍 How to Verify
Check if Vulnerable:
Check version numbers in affected applications: Safari (About Safari), iTunes (Help > About iTunes), iCloud (Help > About iCloud), iOS/iPadOS (Settings > General > About), tvOS (Settings > General > About).Check Version:
Windows: wmic product get name,version | findstr /i "iTunes iCloud" | macOS: sw_vers | iOS/iPadOS/tvOS: Settings > General > AboutVerify Fix Applied:
Verify version numbers match or exceed patched versions listed in fix_official section.📡 Detection & Monitoring
Log Indicators:
- Unusual cross-origin requests in web server logs
- Multiple failed same-origin policy validations in browser logs
Network Indicators:
- Suspicious cross-domain requests from single client
- Unusual traffic patterns to multiple domains from same source
SIEM Query:
source="web_server" AND (http_referer CONTAINS malicious_domain OR origin_header != host_header)🔗 References
- https://support.apple.com/en-us/HT210918
- https://support.apple.com/en-us/HT210920
- https://support.apple.com/en-us/HT210922
- https://support.apple.com/en-us/HT210923
- https://support.apple.com/en-us/HT210947
- https://support.apple.com/en-us/HT210948
- https://support.apple.com/en-us/HT210918
- https://support.apple.com/en-us/HT210920
- https://support.apple.com/en-us/HT210922
- https://support.apple.com/en-us/HT210923
- https://support.apple.com/en-us/HT210947
- https://support.apple.com/en-us/HT210948
