CVE-2021-1816
📋 TL;DR
This CVE describes a buffer overflow vulnerability in Apple's iOS, iPadOS, watchOS, and tvOS that allows malicious applications to execute arbitrary code with kernel privileges. It affects devices running versions before iOS 14.5, iPadOS 14.5, watchOS 7.4, and tvOS 14.5. Successful exploitation gives attackers complete control over the affected device.
💻 Affected Systems
- iPhone
- iPad
- Apple Watch
- Apple TV
📦 What is this software?
Ipados by Apple
Tvos by Apple
Watchos by Apple
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise with kernel-level privileges, allowing data theft, persistence installation, and lateral movement within networks.
Likely Case
Malicious apps from untrusted sources could gain full system control to steal sensitive data, install backdoors, or conduct surveillance.
If Mitigated
With proper app vetting and security controls, risk is limited to targeted attacks requiring user interaction to install malicious apps.
🎯 Exploit Status
Exploitation requires user to install a malicious application. No public exploit code is known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: iOS 14.5, iPadOS 14.5, watchOS 7.4, tvOS 14.5
Vendor Advisory: https://support.apple.com/en-us/HT212317
Restart Required: Yes
Instructions:
1. Go to Settings > General > Software Update. 2. Download and install iOS 14.5/iPadOS 14.5/watchOS 7.4/tvOS 14.5 or later. 3. Restart device after installation completes.
🔧 Temporary Workarounds
Restrict App Installation Sources
allOnly allow app installations from the official App Store to prevent malicious app installation.
Settings > General > Device Management > Enable 'Allow Apps From App Store Only'
🧯 If You Can't Patch
- Implement strict mobile device management (MDM) policies to control app installations
- Segment affected devices on isolated network segments to limit lateral movement
🔍 How to Verify
Check if Vulnerable:
Check device version in Settings > General > About > Version. If version is below iOS 14.5, iPadOS 14.5, watchOS 7.4, or tvOS 14.5, device is vulnerable.Check Version:
Settings > General > About > VersionVerify Fix Applied:
Verify device is running iOS 14.5+, iPadOS 14.5+, watchOS 7.4+, or tvOS 14.5+ in Settings > General > About > Version.📡 Detection & Monitoring
Log Indicators:
- Unexpected kernel module loads
- Privilege escalation attempts
- Suspicious app installation events
Network Indicators:
- Unusual outbound connections from mobile devices
- Command and control traffic patterns
SIEM Query:
source="apple_mdm" AND (event="app_install" AND app_source!="app_store") OR (event="privilege_escalation")