CVE-2020-9850: Apple iCloud RCE Vulnerability

CVE-2020-9850 Overview

CVE-2020-9850 is a logic issue vulnerability affecting multiple Apple products including iOS, iPadOS, Safari, tvOS, watchOS, iTunes, and iCloud for Windows. The vulnerability stems from improper restrictions in the WebKit browser engine, which allows a remote attacker to potentially achieve arbitrary code execution on affected devices. This vulnerability is particularly concerning due to its network-based attack vector requiring no user interaction or privileges, making it an attractive target for threat actors.

Critical Impact

Remote attackers can achieve arbitrary code execution on vulnerable Apple devices through a network-based attack without requiring authentication or user interaction.

Affected Products

• Apple iOS versions prior to 13.5
• Apple iPadOS versions prior to 13.5
• Apple Safari versions prior to 13.1.1
• Apple tvOS versions prior to 13.4.5
• Apple watchOS versions prior to 6.2.5
• Apple iTunes for Windows versions prior to 12.10.7
• Apple iCloud for Windows versions prior to 11.2 and 7.19

Discovery Timeline

• June 9, 2020 - CVE-2020-9850 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2020-9850

Vulnerability Analysis

This vulnerability is classified as a logic issue within Apple's WebKit rendering engine, which powers Safari and other Apple applications that display web content. The flaw exists due to insufficient restrictions in how WebKit processes certain operations, allowing attackers to bypass security controls that would normally prevent unauthorized code execution.

The vulnerability can be exploited remotely over a network without requiring any privileges or user interaction. When successfully exploited, an attacker can execute arbitrary code with the privileges of the targeted application, potentially leading to complete device compromise. This includes access to sensitive data, installation of malware, or further lateral movement within a network.

Root Cause

The root cause of CVE-2020-9850 lies in a logic error within WebKit's processing routines. The implementation failed to properly restrict certain operations, allowing attackers to manipulate the execution flow in unintended ways. Apple addressed this issue by implementing improved restrictions to ensure proper validation and handling of the affected operations.

Attack Vector

The attack vector for CVE-2020-9850 is network-based, meaning an attacker can exploit this vulnerability remotely. The attack complexity is low, requiring neither authentication nor user interaction to successfully execute. A typical exploitation scenario involves:

1. An attacker crafting malicious web content designed to trigger the logic flaw
2. The victim's device processing the malicious content through WebKit
3. The logic issue allowing bypass of security restrictions
4. Arbitrary code execution occurring on the victim's device

The vulnerability affects the core WebKit engine, impacting multiple Apple platforms and applications that rely on this component for rendering web content.

Detection Methods for CVE-2020-9850

Indicators of Compromise

• Unusual network connections from Safari or WebKit-based applications to unknown external servers
• Unexpected process spawning or child processes from browser or media applications
• Anomalous memory allocation patterns in WebKit-related processes
• Suspicious JavaScript or web content execution patterns in system logs

Detection Strategies

• Monitor for unusual WebKit process behavior including unexpected crashes or restarts
• Implement network traffic analysis to detect potential exploitation attempts targeting Apple devices
• Deploy endpoint detection solutions capable of identifying WebKit-based exploitation attempts
• Review system logs for signs of unauthorized code execution following web browsing activity

Monitoring Recommendations

• Enable verbose logging on Apple devices where possible to capture WebKit-related events
• Implement network-level monitoring for traffic to and from Apple devices that may indicate exploitation
• Utilize SentinelOne's behavioral AI to detect anomalous process activity associated with WebKit exploitation
• Configure alerting for any unauthorized applications or processes spawned by Safari or other WebKit-dependent apps

How to Mitigate CVE-2020-9850

Immediate Actions Required

• Update all Apple devices to the latest available software versions immediately
• Prioritize updating iOS devices to version 13.5 or later
• Update Safari to version 13.1.1 or later on macOS systems
• Update iTunes and iCloud applications on Windows systems to the patched versions
• Consider restricting web browsing on unpatched devices until updates can be applied

Patch Information

Apple has released security updates addressing this vulnerability across all affected products. The following updates contain the fix for CVE-2020-9850:

• iOS 13.5 and iPadOS 13.5 - See Apple Support Article HT211168
• tvOS 13.4.5 - See Apple Support Article HT211171
• watchOS 6.2.5 - See Apple Support Article HT211175
• Safari 13.1.1 - See Apple Support Article HT211177
• iTunes 12.10.7 for Windows - See Apple Support Article HT211178
• iCloud for Windows 11.2 - See Apple Support Article HT211179
• iCloud for Windows 7.19 - See Apple Support Article HT211181

Workarounds

• Limit web browsing on affected devices to trusted sites only until patches can be applied
• Disable JavaScript in Safari settings to reduce the attack surface (may impact functionality)
• Use network-level filtering to block access to potentially malicious websites
• Consider using alternative browsers on Windows systems until iTunes and iCloud are updated

# iOS/iPadOS version verification
# Navigate to: Settings > General > About > Software Version
# Ensure version is 13.5 or later

# macOS Safari version check
# Safari > About Safari
# Ensure version is 13.1.1 or later

# Windows iTunes/iCloud update
# Use Apple Software Update or download directly from Apple