CVE-2023-40113: Google Android Information Disclosure Flaw

CVE-2023-40113 Overview

CVE-2023-40113 is a missing authorization vulnerability affecting Google Android's TelephonyProvider component. The flaw exists in multiple locations within the platform where apps can access cross-user message data due to a missing permission check. This vulnerability enables local information disclosure without requiring additional execution privileges or user interaction, making it particularly concerning for multi-user Android deployments such as enterprise environments and shared devices.

Critical Impact

Applications on affected Android devices can potentially access SMS/MMS message data belonging to other user profiles on the same device, bypassing intended user isolation boundaries.

Affected Products

• Google Android 11.0
• Google Android 12.0
• Google Android 12.1
• Google Android 13.0

Discovery Timeline

• 2023-11-01 - Google releases security patch in Android Security Bulletin November 2023
• 2024-02-15 - CVE CVE-2023-40113 published to NVD
• 2024-12-13 - Last updated in NVD database

Technical Details for CVE-2023-40113

Vulnerability Analysis

This vulnerability stems from improper access control within Android's TelephonyProvider, which is responsible for managing SMS and MMS message storage. The missing permission check allows applications to query and access message data that belongs to user profiles other than the one currently active. Android's multi-user architecture is designed to provide strong isolation between user profiles, particularly for sensitive data like personal communications. The failure to enforce proper permission checks in the TelephonyProvider component undermines this security model.

The vulnerability can be exploited locally by a malicious application installed on the device. Once exploited, an attacker gains read access to confidential messaging data across user boundaries. The attack does not require any user interaction, meaning a background application could silently harvest message data without the user's knowledge.

Root Cause

The root cause is classified as CWE-862 (Missing Authorization). The TelephonyProvider component fails to properly verify whether the requesting application has the necessary permissions to access message data belonging to a specific user profile. This authorization check should occur when processing content provider queries but was absent in the affected code paths. The fix implemented by Google adds the missing permission validation to ensure that applications can only access message data within their authorized user scope.

Attack Vector

The attack vector is local, requiring a malicious application to be installed on the target Android device. The attacker application does not require elevated privileges beyond standard application permissions. The exploitation flow involves:

1. A malicious application is installed on a multi-user Android device
2. The application queries the TelephonyProvider content provider
3. Due to the missing permission check, the query returns message data from other user profiles
4. The attacker can exfiltrate SMS/MMS content, phone numbers, timestamps, and other metadata

The vulnerability is particularly impactful in scenarios where devices are shared between users with different trust levels, such as corporate BYOD devices with work profiles, shared family tablets, or educational devices.

Detection Methods for CVE-2023-40113

Indicators of Compromise

• Unusual content provider queries targeting content://sms or content://mms from unexpected applications
• Applications accessing TelephonyProvider data across user profile boundaries
• Unexpected data exfiltration patterns from applications with messaging-related permissions
• Anomalous inter-process communication involving the com.android.providers.telephony package

Detection Strategies

• Monitor application behavior for unauthorized content provider access patterns
• Implement mobile device management (MDM) solutions that can detect applications querying sensitive content providers
• Deploy endpoint detection solutions capable of analyzing Android application behavior at runtime
• Review installed application permissions for unnecessary access to SMS/MMS data

Monitoring Recommendations

• Enable audit logging for content provider access on managed Android devices
• Deploy SentinelOne Singularity Mobile to detect exploitation attempts and anomalous application behavior
• Implement network-level monitoring for potential data exfiltration following message data access
• Regularly audit installed applications on multi-user devices for suspicious permission requests

How to Mitigate CVE-2023-40113

Immediate Actions Required

• Update affected Android devices to the November 2023 security patch level or later
• Review and audit installed applications on multi-user devices for unnecessary permissions
• Consider removing or disabling untrusted applications on devices containing sensitive message data
• Implement application allowlisting on enterprise-managed devices to prevent malicious application installation

Patch Information

Google has addressed this vulnerability in the Android Security Bulletin November 2023. The fix is available in the TelephonyProvider update with commit hash 64ca6ba981745875dbf2064e0b2a47f8194c4f0a. Organizations should ensure all Android devices running versions 11.0 through 13.0 are updated to at least the 2023-11-01 security patch level.

Workarounds

• Limit the number of user profiles on devices that cannot be immediately patched
• Restrict application installation to trusted sources and vetted applications only
• Implement mobile device management (MDM) policies to enforce application restrictions
• Consider isolating sensitive communications to devices that have been patched

# Verify Android security patch level
adb shell getprop ro.build.version.security_patch
# Should return 2023-11-01 or later for patched devices