CVE-2021-30957
📋 TL;DR
This CVE describes a buffer overflow vulnerability in Apple's audio file processing components. Attackers can exploit it by crafting malicious audio files to execute arbitrary code on affected devices. Users of macOS, iOS, iPadOS, watchOS, and tvOS before specific versions are vulnerable.
💻 Affected Systems
- macOS
- iOS
- iPadOS
- watchOS
- tvOS
📦 What is this software?
Ipados by Apple
Macos by Apple
macOS is Apple's desktop and laptop operating system powering Mac computers used by millions of professionals, developers, creative professionals, and enterprise users worldwide. Built on a Unix foundation with the Darwin kernel and modern Cocoa frameworks, macOS delivers a seamless ecosystem integr...
Learn more about Macos →Macos by Apple
macOS is Apple's desktop and laptop operating system powering Mac computers used by millions of professionals, developers, creative professionals, and enterprise users worldwide. Built on a Unix foundation with the Darwin kernel and modern Cocoa frameworks, macOS delivers a seamless ecosystem integr...
Learn more about Macos →Tvos by Apple
Watchos by Apple
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining full control over the device, potentially leading to data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Malicious audio file execution leading to application crashes, data exfiltration, or installation of malware/spyware on the device.
If Mitigated
Denial of service through application crashes if memory protections are active, but no code execution.
🎯 Exploit Status
Exploitation requires user interaction to open a malicious audio file, but no authentication is needed once the file is processed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Monterey 12.1, iOS 15.2, iPadOS 15.2, watchOS 8.3, tvOS 15.2
Vendor Advisory: https://support.apple.com/en-us/HT212975
Restart Required: Yes
Instructions:
1. Open Settings/System Preferences. 2. Navigate to Software Update. 3. Download and install the latest available update. 4. Restart the device when prompted.
🔧 Temporary Workarounds
Disable automatic audio file processing
allPrevent automatic opening of audio files from untrusted sources
Use application sandboxing
macOSConfigure audio applications to run in restricted environments
🧯 If You Can't Patch
- Implement strict file type filtering on email gateways and web proxies to block suspicious audio files
- Deploy endpoint protection that can detect and block malicious audio file execution
🔍 How to Verify
Check if Vulnerable:
Check system version against affected versions list. On macOS: System Preferences > About This Mac. On iOS/iPadOS: Settings > General > About.Check Version:
macOS: sw_vers -productVersion, iOS/iPadOS: Settings > General > About > VersionVerify Fix Applied:
Verify system version is equal to or newer than the patched versions listed in the fix information.📡 Detection & Monitoring
Log Indicators:
- Unexpected audio file processing errors
- Application crashes in audio-related processes
- Memory access violation logs
Network Indicators:
- Downloads of unusual audio file types from untrusted sources
- Outbound connections from audio applications to suspicious IPs
SIEM Query:
source="*system.log*" AND ("audio" OR "coreaudio") AND ("crash" OR "segfault" OR "overflow")🔗 References
- https://support.apple.com/en-us/HT212975
- https://support.apple.com/en-us/HT212976
- https://support.apple.com/en-us/HT212978
- https://support.apple.com/en-us/HT212980
- https://support.apple.com/kb/HT212979
- https://support.apple.com/en-us/HT212975
- https://support.apple.com/en-us/HT212976
- https://support.apple.com/en-us/HT212978
- https://support.apple.com/en-us/HT212980
- https://support.apple.com/kb/HT212979
