CVE-2023-41989: Apple macOS Lock Screen RCE Vulnerability

CVE-2023-41989 Overview

CVE-2023-41989 is a privilege escalation vulnerability affecting Apple macOS that allows an attacker with physical access to execute arbitrary code as root from the Lock Screen. The flaw stems from insufficient restrictions on options available while a device is in a locked state, enabling attackers to bypass authentication controls and gain root-level access without proper credentials.

Critical Impact

An attacker with physical access to a macOS device can execute arbitrary code with root privileges from the Lock Screen, potentially leading to complete system compromise.

Affected Products

• Apple macOS versions prior to macOS Sonoma 14.1
• Apple macOS (all vulnerable versions as specified in cpe:2.3:o:apple:macos::::::::)

Discovery Timeline

• October 25, 2023 - CVE-2023-41989 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2023-41989

Vulnerability Analysis

This vulnerability represents a significant authentication bypass that allows local privilege escalation through the macOS Lock Screen interface. The attack requires physical access to the device but does not require any prior privileges or user interaction to exploit. The flaw exists in how macOS handles available options and functionality when the device is in a locked state.

When a macOS device is locked, certain system components remain accessible to facilitate legitimate functionality. However, insufficient restrictions on these accessible options allowed an attacker to leverage this access path to execute arbitrary commands with root-level privileges. The attack completely bypasses the authentication mechanisms that would normally protect the system when locked.

Root Cause

The root cause of this vulnerability lies in improper access control implementation within the macOS Lock Screen interface. Apple's security architecture failed to adequately restrict the options and functionality available to users (or attackers) when the device was locked. This allowed an exploitation path that circumvented normal authentication requirements.

The specific weakness has been classified as "NVD-CWE-noinfo," indicating the precise technical mechanism has not been publicly disclosed in detail, likely to prevent exploitation before systems could be patched.

Attack Vector

The attack requires physical access to the target macOS device. Once physical access is obtained, an attacker can interact with the Lock Screen interface to execute arbitrary code with root privileges. The exploitation does not require:

• Prior authentication to the system
• User interaction from the legitimate owner
• Any special privileges or accounts

The physical access requirement limits the attack surface to scenarios where an attacker can physically interact with the target device, such as:

• Stolen or unattended laptops
• Corporate environments with shared workspaces
• Public settings where devices may be temporarily left unattended

Due to the sensitive nature of this vulnerability and to protect users, specific exploitation techniques are not publicly documented. The vulnerability allows code execution through the Lock Screen interface by leveraging improperly restricted options. For technical details, refer to Apple Support Document HT213984 and the Full Disclosure mailing list.

Detection Methods for CVE-2023-41989

Indicators of Compromise

• Unexpected processes running with root privileges that were initiated while the device was locked
• System logs showing authentication events or process executions during times when the device should have been locked and unattended
• Evidence of privilege escalation without corresponding login events

Detection Strategies

• Monitor system logs for process executions that occur without prior authentication events
• Implement endpoint detection and response (EDR) solutions that can identify anomalous root-level process creation
• Review security audit logs for suspicious activity patterns during device lock states
• Deploy SentinelOne Singularity Platform to detect and respond to unauthorized privilege escalation attempts

Monitoring Recommendations

• Enable comprehensive audit logging on macOS devices, particularly for authentication events and process creation
• Configure alerts for root-level process executions that don't correspond to expected administrative activities
• Monitor for FileVault or other security feature modifications that could indicate post-compromise activity

How to Mitigate CVE-2023-41989

Immediate Actions Required

• Update all macOS systems to macOS Sonoma 14.1 or later immediately
• Ensure physical security controls are in place for all macOS devices
• Review security policies for unattended device handling
• Deploy endpoint protection solutions capable of detecting unauthorized code execution

Patch Information

Apple has addressed this vulnerability in macOS Sonoma 14.1 by restricting the options offered on a locked device. The patch prevents the exploitation path that allowed code execution from the Lock Screen.

To update your macOS system:

1. Navigate to System Settings > General > Software Update
2. Install macOS Sonoma 14.1 or later
3. Restart the device to complete the installation

For detailed patch information, refer to Apple Support Document HT213984 and Apple Knowledge Base HT214037.

Workarounds

• Implement strict physical security controls to prevent unauthorized access to macOS devices
• Enable FileVault full-disk encryption to protect data even if physical access is obtained
• Configure automatic screen lock with short timeout periods to minimize exposure windows
• Consider implementing additional endpoint security solutions until patches can be applied

# Enable automatic screen lock with 1-minute timeout
sudo defaults write com.apple.screensaver askForPassword -int 1
sudo defaults write com.apple.screensaver askForPasswordDelay -int 0

# Verify FileVault encryption status
sudo fdesetup status