CVE-2023-27937: Apple iPadOS RCE Vulnerability

CVE-2023-27937 Overview

CVE-2023-27937 is an integer overflow vulnerability affecting multiple Apple operating systems including macOS, iOS, iPadOS, tvOS, and watchOS. The vulnerability exists in the plist parsing functionality, where improper input validation allows a maliciously crafted property list file to trigger an integer overflow condition. Successful exploitation can result in unexpected application termination or arbitrary code execution.

Critical Impact

Parsing a maliciously crafted plist file may lead to arbitrary code execution, potentially allowing an attacker to gain full control over the affected device.

Affected Products

• Apple macOS Ventura (versions prior to 13.3)
• Apple macOS Monterey (versions prior to 12.6.4)
• Apple macOS Big Sur (versions prior to 11.7.5)
• Apple iOS (versions prior to 16.4)
• Apple iPadOS (versions prior to 16.4)
• Apple tvOS (versions prior to 16.4)
• Apple watchOS (versions prior to 9.4)

Discovery Timeline

• May 8, 2023 - CVE-2023-27937 published to NVD
• January 29, 2025 - Last updated in NVD database

Technical Details for CVE-2023-27937

Vulnerability Analysis

This vulnerability stems from CWE-190 (Integer Overflow or Wraparound), a memory corruption class vulnerability that occurs when an arithmetic operation attempts to create a numeric value that exceeds the range that can be represented within the available storage space. In this case, the integer overflow occurs during the parsing of property list (plist) files, a common data format used extensively throughout Apple's ecosystem for storing serialized objects and configuration data.

When a specially crafted plist file is processed, the parsing logic fails to adequately validate input values before performing arithmetic operations. This can cause an integer to wrap around to an unexpected value, leading to incorrect memory allocation sizes or buffer bounds calculations. The consequence of such corruption can range from application crashes (denial of service) to arbitrary code execution if an attacker can control the memory corruption in a predictable manner.

The local attack vector requires user interaction, meaning an attacker would need to convince a user to open or process a malicious plist file. This could be achieved through social engineering, malicious email attachments, or compromised applications that process plist data.

Root Cause

The root cause of CVE-2023-27937 is insufficient input validation in the plist parsing routines. When processing numeric values or size fields within a plist structure, the code performs arithmetic operations without properly checking whether the result would exceed the maximum value representable by the integer type. This allows an attacker to craft specific values that, when combined through arithmetic operations, cause the integer to overflow and wrap to a small or negative value.

Attack Vector

The attack vector for this vulnerability is local and requires user interaction. An attacker must craft a malicious plist file containing specific values designed to trigger the integer overflow during parsing. The attack scenario typically involves:

1. Creating a specially crafted plist file with values that cause integer overflow during parsing
2. Delivering the malicious file to the target through email attachments, downloads, or other file transfer mechanisms
3. Tricking the user into opening or processing the file, either directly or through an application that handles plist data
4. The parsing operation triggers the integer overflow, leading to memory corruption
5. Depending on the memory state and attacker control, this can result in code execution

The vulnerability affects plist parsing across the Apple ecosystem, meaning any application or system component that processes plist files could potentially be exploited.

Detection Methods for CVE-2023-27937

Indicators of Compromise

• Unexpected application crashes when processing plist files, particularly those from untrusted sources
• Crash logs indicating memory corruption or access violations in plist parsing components
• Unusual system behavior following the opening of plist files received via email or downloaded from the internet
• Evidence of exploitation attempts through malformed plist files in user download directories or email attachments

Detection Strategies

• Monitor for abnormal crash patterns in applications that commonly process plist files
• Implement file integrity monitoring to detect suspicious plist files with unusual size or structure characteristics
• Deploy endpoint detection solutions capable of identifying integer overflow exploitation patterns
• Review system logs for crash reports with signatures consistent with memory corruption in plist handling

Monitoring Recommendations

• Enable crash reporting and analysis to identify potential exploitation attempts through crash signatures
• Monitor network traffic for downloads of plist files from untrusted or suspicious sources
• Implement user behavior analytics to detect unusual file access patterns involving plist files
• Configure SentinelOne agents to monitor for behavioral indicators associated with memory corruption exploitation

How to Mitigate CVE-2023-27937

Immediate Actions Required

• Update all Apple devices to the latest patched versions immediately (macOS Ventura 13.3, macOS Monterey 12.6.4, macOS Big Sur 11.7.5, iOS 16.4, iPadOS 16.4, tvOS 16.4, watchOS 9.4)
• Educate users about the risks of opening plist files from untrusted sources
• Review and restrict which applications have permissions to process plist files from external sources
• Implement application allowlisting to prevent untrusted applications from executing

Patch Information

Apple has addressed this vulnerability through improved input validation in the plist parsing routines. Security updates are available for all affected platforms. Detailed patch information can be found in the following Apple Security Advisories:

• Apple Support Article #HT213670 - macOS Ventura 13.3
• Apple Support Article #HT213674 - tvOS 16.4
• Apple Support Article #HT213675 - macOS Big Sur 11.7.5
• Apple Support Article #HT213676 - macOS Monterey 12.6.4
• Apple Support Article #HT213677 - watchOS 9.4
• Apple Support Article #HT213678 - iOS 16.4 and iPadOS 16.4

Organizations should prioritize deployment of these patches across all managed Apple devices.

Workarounds

• Configure email security solutions to quarantine or block plist file attachments from external senders
• Implement Mobile Device Management (MDM) policies to restrict installation of applications from untrusted sources
• Use application sandboxing to limit the impact of potential exploitation
• Deploy endpoint protection solutions like SentinelOne that can detect and prevent memory corruption exploitation attempts

# Example: Check current macOS version to verify patch status
sw_vers -productVersion

# Verify iOS/iPadOS version on managed devices via MDM
# Expected patched versions:
# macOS Ventura: 13.3 or later
# macOS Monterey: 12.6.4 or later
# macOS Big Sur: 11.7.5 or later
# iOS/iPadOS: 16.4 or later
# tvOS: 16.4 or later
# watchOS: 9.4 or later