CVE-2019-8773
📋 TL;DR
CVE-2019-8773 is a memory corruption vulnerability in Apple's WebKit browser engine that allows arbitrary code execution when processing malicious web content. It affects Safari, iOS, iPadOS, tvOS, watchOS, iCloud for Windows, and iTunes for Windows. Attackers can exploit this by tricking users into visiting specially crafted websites.
💻 Affected Systems
- Safari
- iOS
- iPadOS
- tvOS
- watchOS
- iCloud for Windows
- iTunes for Windows
📦 What is this software?
Icloud by Apple
Icloud by Apple
Ipad Os by Apple
Itunes by Apple
Safari by Apple
Tvos by Apple
Watchos by Apple
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining complete control over the affected device, allowing data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Malicious website executes arbitrary code in browser context, potentially stealing cookies, session tokens, or installing malware on the device.
If Mitigated
With proper patching and security controls, impact is limited to isolated browser crashes or denial of service.
🎯 Exploit Status
Exploitation requires user interaction (visiting malicious website) but no authentication. Memory corruption vulnerabilities typically require specific conditions to achieve reliable code execution.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Safari 13.0.1, iOS 13.1, iPadOS 13.1, tvOS 13, watchOS 6, iCloud for Windows 10.7, iCloud for Windows 7.14, iTunes 12.10.1 for Windows
Vendor Advisory: https://support.apple.com/en-us/HT210603
Restart Required: Yes
Instructions:
1. Update Safari through System Preferences > Software Update. 2. Update iOS/iPadOS via Settings > General > Software Update. 3. Update tvOS via Settings > System > Software Updates. 4. Update watchOS via iPhone Watch app > General > Software Update. 5. Update iCloud/iTunes for Windows via Apple Software Update or Microsoft Store.
🔧 Temporary Workarounds
Disable JavaScript
allTemporarily disable JavaScript in Safari to prevent exploitation through malicious web content
Safari > Preferences > Security > uncheck 'Enable JavaScript'
Use Alternative Browser
allUse non-WebKit based browsers (Chrome, Firefox) until patches are applied
🧯 If You Can't Patch
- Implement network filtering to block known malicious domains and restrict web browsing to trusted sites only
- Enable application whitelisting to prevent unauthorized code execution from browser processes
🔍 How to Verify
Check if Vulnerable:
Check version numbers: Safari (About Safari), iOS/iPadOS (Settings > General > About), tvOS (Settings > General > About), watchOS (iPhone Watch app > General > About), iCloud/iTunes for Windows (Help > About)Check Version:
Safari: safari --version (macOS Terminal), iOS: Settings > General > About > VersionVerify Fix Applied:
Confirm version numbers match or exceed patched versions listed in fix_official section📡 Detection & Monitoring
Log Indicators:
- Safari/WebKit process crashes with memory access violations
- Unexpected child processes spawned from Safari/WebKit
Network Indicators:
- Outbound connections to suspicious domains following web browsing
- Unusual network traffic patterns from browser processes
SIEM Query:
process_name:safari AND (event_id:1000 OR event_id:1001) OR process_parent_name:safari AND process_name:cmd.exe🔗 References
- https://support.apple.com/en-us/HT210603
- https://support.apple.com/en-us/HT210604
- https://support.apple.com/en-us/HT210605
- https://support.apple.com/en-us/HT210607
- https://support.apple.com/en-us/HT210635
- https://support.apple.com/en-us/HT210636
- https://support.apple.com/en-us/HT210637
- https://support.apple.com/en-us/HT210603
- https://support.apple.com/en-us/HT210604
- https://support.apple.com/en-us/HT210605
- https://support.apple.com/en-us/HT210607
- https://support.apple.com/en-us/HT210635
- https://support.apple.com/en-us/HT210636
- https://support.apple.com/en-us/HT210637
