CVE-2024-40840: Apple iPadOS Information Disclosure Flaw

CVE-2024-40840 Overview

CVE-2024-40840 is a state management vulnerability affecting Apple iOS and iPadOS that allows an attacker with physical access to a device to use Siri to access sensitive user data. The vulnerability stems from improper state management within the Siri voice assistant feature, which fails to adequately restrict access to protected information when the device is locked or in certain states.

Critical Impact

An attacker with physical access to an affected iPhone or iPad can leverage Siri to bypass security controls and access sensitive user data without proper authentication.

Affected Products

• Apple iOS versions prior to 18
• Apple iPadOS versions prior to 18

Discovery Timeline

• 2024-09-17 - CVE CVE-2024-40840 published to NVD
• 2025-11-04 - Last updated in NVD database

Technical Details for CVE-2024-40840

Vulnerability Analysis

This vulnerability exists in the state management logic of Apple's Siri implementation on iOS and iPadOS devices. When an attacker has physical access to an affected device, they can invoke Siri through hardware buttons or voice commands and potentially access sensitive user data that should be protected by the device's lock screen or other security mechanisms.

The vulnerability requires physical proximity to the target device, limiting its exploitability to scenarios where an attacker can directly interact with the hardware. However, the impact on confidentiality is significant as successful exploitation allows unauthorized access to protected user information.

Root Cause

The root cause is improper state management in how Siri handles access control checks when processing user requests. The system fails to properly validate the device's security state or user authentication status before allowing Siri to retrieve or display sensitive information. This creates a gap between the expected security behavior (data protection when locked) and the actual implementation.

Attack Vector

The attack requires physical access to the target device. An attacker must be able to:

1. Gain physical possession of or proximity to the victim's iPhone or iPad
2. Activate Siri through physical interaction (Home button, Side button, or "Hey Siri" if enabled)
3. Issue voice commands to Siri that request access to sensitive user data
4. Exploit the state management flaw to bypass normal access restrictions

Due to the physical access requirement, this vulnerability is most concerning in scenarios such as device theft, unattended devices in public spaces, or insider threat situations. The attack does not require prior privileges or user interaction beyond the attacker's own physical manipulation of the device.

Detection Methods for CVE-2024-40840

Indicators of Compromise

• Unexpected Siri activation history on a locked device
• Evidence of unauthorized access to contacts, messages, or other sensitive data through Siri logs
• User reports of data access they did not authorize

Detection Strategies

• Monitor for unusual Siri usage patterns, particularly on devices that should be locked
• Implement mobile device management (MDM) solutions that can track and alert on suspicious device interactions
• Review device audit logs for Siri-related activities during periods when the device was expected to be idle

Monitoring Recommendations

• Deploy enterprise MDM solutions to maintain visibility into device security state
• Enable comprehensive logging on managed devices where supported
• Educate users to report any signs of unauthorized device access or unexpected Siri behavior

How to Mitigate CVE-2024-40840

Immediate Actions Required

• Update all affected devices to iOS 18 or iPadOS 18 immediately
• Restrict Siri access when the device is locked via Settings > Siri & Search > Allow Siri When Locked
• Enable strong device passcodes and Face ID/Touch ID authentication
• Consider disabling "Hey Siri" voice activation to reduce attack surface

Patch Information

Apple has addressed this vulnerability in iOS 18 and iPadOS 18 through improved state management. The fix ensures proper validation of device security state before allowing Siri to access sensitive user data. Organizations and users should apply these updates immediately. For detailed patch information, refer to the Apple Support Document.

Workarounds

• Disable Siri entirely if the feature is not essential (Settings > Siri & Search)
• Disable "Allow Siri When Locked" to prevent Siri activation on locked devices
• Maintain physical control of devices and avoid leaving them unattended
• Use device management policies to enforce Siri restrictions across enterprise-managed devices

# iOS MDM Configuration Profile Settings (Example)
# Restrict Siri when device is locked
# Deploy via MDM solution to managed devices

# Key restriction settings:
# allowAssistant: true (or false to disable entirely)
# allowAssistantWhileLocked: false
# forceAssistantProfanityFilter: true