CVE-2020-9871 – This vulnerability allows arbitrary code execut... (How to Fix)

Q: What is the severity of CVE-2020-9871?

CVE-2020-9871 has a CVSS score of 7.8 (HIGH). This vulnerability allows arbitrary code execution by processing a maliciously crafted image due to an out-of-bounds write memory corruption issue. It affects Apple iOS, iPadOS, macOS, tvOS, watchOS, iTunes for Windows, and iCloud for Windows. Attackers can exploit this to run malicious code on affected devices.

📋 TL;DR

This vulnerability allows arbitrary code execution by processing a maliciously crafted image due to an out-of-bounds write memory corruption issue. It affects Apple iOS, iPadOS, macOS, tvOS, watchOS, iTunes for Windows, and iCloud for Windows. Attackers can 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 before 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 is triggered when processing malicious images, which could occur through various applications including web browsers, email clients, or image viewers.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

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

🟠

Likely Case

Malicious code execution with user-level privileges, potentially leading to data exfiltration, ransomware deployment, or spyware installation.

🟢

If Mitigated

Limited impact with proper network segmentation and application sandboxing, potentially containing the exploit to the affected application.

🌐 Internet-Facing: MEDIUM

🏢 Internal Only: HIGH

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires the victim to process a malicious image, which could be delivered via email, web, or messaging apps. No public exploit code is known, but the vulnerability is serious and could be weaponized.

🛠️ 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. Open Settings (iOS/iPadOS/watchOS) or System Preferences (macOS). 2. Navigate to Software Update. 3. Download and install the latest update. 4. For Windows applications, update via Apple Software Update or download from Apple's website.

🔧 Temporary Workarounds

Disable automatic image processing

all

Configure email clients and web browsers to not automatically load or process images from untrusted sources.

Use application sandboxing

all

Ensure applications that process images run with minimal privileges and are properly sandboxed.

🧯 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 and malicious behavior.

🔍 How to Verify

Check if Vulnerable:

Check the current version of your Apple device or software against the patched versions listed above.

Check Version:

iOS/iPadOS: Settings > General > About > Version; macOS: Apple menu > About This Mac; Windows: For iTunes/iCloud, open the application and check About menu.

Verify Fix Applied:

Verify that the installed version matches or exceeds the patched version numbers provided.

📡 Detection & Monitoring

Log Indicators:

Unexpected process crashes in image processing applications
Memory access violation errors in system logs
Suspicious image file processing from untrusted sources

Network Indicators:

Unusual outbound connections from devices after processing images
Downloads of suspicious image files from external sources

SIEM Query:

source="*apple*" AND (event_type="crash" OR error="memory" OR process="*image*")

📊 Metadata

CVE ID: CVE-2020-9871

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

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🔗 Related Vulnerabilities

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