CVE-2023-40076: Google Android Privilege Escalation Flaw

CVE-2023-40076 Overview

CVE-2023-40076 is a local privilege escalation vulnerability in Google Android's CredentialManagerUi component. The flaw exists in the createPendingIntent function of CredentialManagerUi.java, where a permissions bypass allows an attacker to access credentials belonging to other users on the same device. This vulnerability can be exploited locally without requiring any user interaction, making it a significant concern for multi-user Android environments.

Critical Impact

Successful exploitation allows unauthorized access to other users' credentials stored on the device, enabling local privilege escalation without requiring additional execution privileges or user interaction.

Affected Products

• Google Android 14.0

Discovery Timeline

• 2023-12-04 - CVE-2023-40076 published to NVD
• 2025-05-29 - Last updated in NVD database

Technical Details for CVE-2023-40076

Vulnerability Analysis

This vulnerability stems from improper permission handling in the Android Credential Manager UI component. The createPendingIntent method in CredentialManagerUi.java fails to properly enforce user-level permission boundaries when creating pending intents for credential operations. This flaw allows a local attacker to bypass normal access controls and retrieve credential information that should be isolated to other user profiles on the device.

The vulnerability is particularly concerning in enterprise or shared device scenarios where multiple users maintain separate credential stores. Android's multi-user architecture is designed to provide isolation between user profiles, but this flaw undermines that security boundary at the credential management layer.

Root Cause

The root cause is classified as CWE-276 (Incorrect Default Permissions). The createPendingIntent method does not properly validate the calling user's permissions before allowing access to credential operations. This results in insufficient access control checks that should restrict credential access to the owning user only. The pending intent creation process lacks proper user context validation, allowing cross-user credential access.

Attack Vector

The attack vector is local, requiring the attacker to have some level of access to the target device. The exploitation path involves:

1. An attacker with local access to an Android 14.0 device executes code within their own user context
2. The malicious code invokes the vulnerable createPendingIntent method in CredentialManagerUi.java
3. Due to the permissions bypass, the pending intent is created without proper user boundary enforcement
4. The attacker can then access credentials stored by other users on the same device
5. No additional execution privileges are needed beyond standard application permissions
6. User interaction is not required for successful exploitation

The vulnerability allows for high confidentiality impact as stored credentials can be exfiltrated, though integrity and availability of the system are not directly affected.

Detection Methods for CVE-2023-40076

Indicators of Compromise

• Unexpected access attempts to credential storage from non-owner user contexts
• Anomalous PendingIntent creation patterns in CredentialManagerUi logs
• Cross-user credential access events that do not match legitimate user switching operations

Detection Strategies

• Monitor Android system logs for suspicious activity involving CredentialManagerUi.java and credential access operations
• Implement application behavior analysis to detect unusual cross-user data access patterns
• Deploy mobile threat detection solutions capable of identifying privilege escalation attempts on Android devices

Monitoring Recommendations

• Enable verbose logging for credential management operations on enterprise-managed Android devices
• Configure SentinelOne Mobile Threat Defense to alert on anomalous credential access behaviors
• Establish baseline user activity patterns to identify deviations that may indicate exploitation attempts

How to Mitigate CVE-2023-40076

Immediate Actions Required

• Apply the Android Security Bulletin December 2023 patch immediately on all affected Android 14.0 devices
• Prioritize patching for devices used in multi-user or shared device scenarios
• Review device access controls and limit local access to trusted users until patches are applied

Patch Information

Google has released a security patch addressing this vulnerability as part of the Android Security Bulletin December 2023. The fix is available in the Android source code repository with commit hash 9b68987df85b681f9362a3cadca6496796d23bbc. Organizations should coordinate with their device manufacturers to ensure the patch is applied through OTA updates or manual firmware updates.

Workarounds

• Restrict physical device access to trusted users only until patches can be applied
• Disable multi-user functionality where not strictly required to reduce the attack surface
• Implement mobile device management (MDM) policies to enforce security baselines and monitor device compliance
• Consider isolating sensitive credential storage to single-user devices in high-security environments

# Verify Android Security Patch Level
adb shell getprop ro.build.version.security_patch
# Expected output should be 2023-12-01 or later for patched devices