CVE-2020-9937 – CVE-2020-9937 is an out-of-bounds write vulnera... (How to Fix)

Q: What is the severity of CVE-2020-9937?

CVE-2020-9937 has a CVSS score of 7.8 (HIGH). CVE-2020-9937 is an out-of-bounds write vulnerability in Apple's image processing components that could allow arbitrary code execution when processing a maliciously crafted image. This affects multiple Apple operating systems and applications including iOS, macOS, tvOS, watchOS, and Windows versions of iTunes and iCloud. Attackers could exploit this to run malicious code on affected devices.

📋 TL;DR

CVE-2020-9937 is an out-of-bounds write vulnerability in Apple's image processing components that could allow arbitrary code execution when processing a maliciously crafted image. This affects multiple Apple operating systems and applications including iOS, macOS, tvOS, watchOS, and Windows versions of iTunes and iCloud. Attackers could exploit this to run malicious code on affected devices.

💻 Affected Systems

Products:

iOS
iPadOS
macOS Catalina
tvOS
watchOS
iTunes for Windows
iCloud for Windows

Versions: Versions prior to iOS 13.6, iPadOS 13.6, macOS Catalina 10.15.6, tvOS 13.4.8, watchOS 6.2.8, iTunes 12.10.8 for Windows, iCloud for Windows 11.3, iCloud for Windows 7.20

Operating Systems: iOS, iPadOS, macOS, tvOS, watchOS, Windows

Default Config Vulnerable: ⚠️ Yes

Notes: All default configurations are vulnerable. The vulnerability exists in the image processing framework used by multiple applications.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Full system compromise with attacker gaining complete control over the device, allowing data theft, persistence installation, and lateral movement.

🟠

Likely Case

Arbitrary code execution in the context of the application processing the image, potentially leading to data exfiltration or further system exploitation.

🟢

If Mitigated

No impact if systems are fully patched or if malicious images are blocked before processing.

🌐 Internet-Facing: MEDIUM - Exploitation requires user interaction (opening malicious image) but could be delivered via web, email, or messaging.

🏢 Internal Only: LOW - Requires user interaction with malicious content, making automated internal exploitation less likely.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires user interaction to process a malicious image. No public exploit code is known, but the vulnerability is serious enough that attackers may develop private exploits.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: iOS 13.6, iPadOS 13.6, macOS Catalina 10.15.6, tvOS 13.4.8, watchOS 6.2.8, iTunes 12.10.8 for Windows, iCloud for Windows 11.3, iCloud for Windows 7.20

Vendor Advisory: https://support.apple.com/kb/HT211288

Restart Required: Yes

Instructions:

1. Go to Settings > General > Software Update on iOS/iPadOS. 2. Go to System Preferences > Software Update on macOS. 3. For Windows applications, update through Apple Software Update or download from Apple's website. 4. Restart devices after installation.

🔧 Temporary Workarounds

Block suspicious image files

all

Use email/web gateways to block potentially malicious image attachments and downloads.

User education

all

Train users not to open image files from untrusted sources.

🧯 If You Can't Patch

Implement network segmentation to isolate vulnerable devices from critical systems
Deploy endpoint detection and response (EDR) solutions to monitor for exploitation attempts

🔍 How to Verify

Check if Vulnerable:

Check current OS/application version against patched versions listed in affected_systems.versions

Check Version:

iOS/iPadOS: Settings > General > About > Version; macOS: Apple menu > About This Mac; Windows apps: Help > About

Verify Fix Applied:

Verify version numbers match or exceed patched versions: iOS/iPadOS ≥13.6, macOS ≥10.15.6, tvOS ≥13.4.8, watchOS ≥6.2.8, iTunes ≥12.10.8, iCloud ≥11.3/7.20

📡 Detection & Monitoring

Log Indicators:

Application crashes in image processing components
Unusual process creation from image viewing applications
Memory access violations in system logs

Network Indicators:

Downloads of suspicious image files from untrusted sources
Outbound connections from image processing applications to unknown IPs

SIEM Query:

Image: (process_name:"Preview" OR process_name:"Photos" OR process_name:"iTunes") AND (event_type:"process_crash" OR event_type:"memory_violation")

📊 Metadata

CVE ID: CVE-2020-9937

CVSS v3 Score: 7.8 (HIGH)

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CWE: CWE-787

Published: October 22, 2020

Last Updated: November 21, 2024

🔗 References

https://support.apple.com/kb/HT211288 Vendor Advisory
https://support.apple.com/kb/HT211289 Vendor Advisory
https://support.apple.com/kb/HT211290 Vendor Advisory
https://support.apple.com/kb/HT211291 Vendor Advisory
https://support.apple.com/kb/HT211293 Vendor Advisory
https://support.apple.com/kb/HT211294 Vendor Advisory
https://support.apple.com/kb/HT211295 Vendor Advisory
https://support.apple.com/kb/HT211288 Vendor Advisory
https://support.apple.com/kb/HT211289 Vendor Advisory
https://support.apple.com/kb/HT211290 Vendor Advisory
https://support.apple.com/kb/HT211291 Vendor Advisory
https://support.apple.com/kb/HT211293 Vendor Advisory
https://support.apple.com/kb/HT211294 Vendor Advisory
https://support.apple.com/kb/HT211295 Vendor Advisory

📤 Share & Export

📄 Export Markdown 📋 Export JSON

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