CVE-2020-0041: Google Android Privilege Escalation Flaw

CVE-2020-0041 Overview

CVE-2020-0041 is an out-of-bounds write vulnerability in the Android kernel's Binder driver, specifically in the binder_transaction function of binder.c. The vulnerability stems from an incorrect bounds check that allows local attackers to escalate privileges on affected Android devices. Exploitation requires no user interaction and no additional execution privileges, making this a particularly dangerous local privilege escalation vulnerability.

Critical Impact

This vulnerability is actively exploited in the wild and is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog. Successful exploitation allows attackers to gain elevated privileges on Android devices without any user interaction.

Affected Products

• Google Android (all kernel versions prior to the March 2020 security patch)

Discovery Timeline

• March 10, 2020 - CVE-2020-0041 published to NVD
• October 23, 2025 - Last updated in NVD database

Technical Details for CVE-2020-0041

Vulnerability Analysis

This vulnerability affects the Android Binder inter-process communication (IPC) mechanism, which is a fundamental component of the Android operating system responsible for facilitating communication between different processes and services. The Binder driver operates at the kernel level and handles transaction data between user-space processes.

The root cause of CVE-2020-0041 lies in the binder_transaction function within binder.c, where an incorrect bounds check fails to properly validate buffer boundaries during transaction processing. This improper validation allows an attacker to trigger an out-of-bounds write condition, corrupting adjacent kernel memory.

Because the Binder driver runs with kernel privileges, successful exploitation of this vulnerability enables local privilege escalation. An attacker with local access to a vulnerable Android device can leverage this flaw to execute arbitrary code in the kernel context, effectively gaining complete control over the device without requiring any user interaction.

Root Cause

The vulnerability originates from CWE-20 (Improper Input Validation) in the bounds checking logic of the binder_transaction function. The function fails to correctly validate the size or boundaries of data being processed during a Binder transaction, allowing writes beyond the intended buffer allocation in kernel memory.

Attack Vector

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

1. A malicious application or process initiating a specially crafted Binder transaction
2. The crafted transaction exploits the incorrect bounds check in binder_transaction
3. The out-of-bounds write corrupts kernel memory structures
4. The attacker leverages the memory corruption to achieve privilege escalation
5. The attacker gains elevated privileges without needing user interaction

The vulnerability mechanism involves manipulating transaction data to exploit the improper bounds validation. When a Binder transaction is processed with maliciously crafted parameters, the kernel fails to properly constrain write operations, leading to memory corruption. For detailed technical analysis, refer to the Android Security Bulletin March 2020.

Detection Methods for CVE-2020-0041

Indicators of Compromise

• Unusual Binder transaction patterns or failures in kernel logs
• Unexpected privilege escalation events from low-privilege applications
• Anomalous kernel crash dumps related to Binder driver operations
• Evidence of applications attempting to access kernel memory regions outside their allocation

Detection Strategies

• Monitor system logs for Binder-related kernel panics or abnormal transaction failures
• Implement runtime application self-protection (RASP) to detect privilege escalation attempts
• Deploy endpoint detection solutions capable of identifying kernel exploitation patterns
• Analyze application behavior for attempts to exploit IPC mechanisms

Monitoring Recommendations

• Enable enhanced logging for Binder driver operations where possible
• Implement security monitoring for kernel-level anomalies on Android devices
• Deploy mobile threat defense solutions that can detect exploitation attempts
• Monitor for applications with unusual permission escalation patterns

How to Mitigate CVE-2020-0041

Immediate Actions Required

• Apply the Android security patch from March 2020 immediately to all affected devices
• Prioritize patching devices in enterprise environments due to confirmed active exploitation
• Remove or disable untrusted applications that could serve as exploitation vectors
• Implement device management policies to enforce security updates

Patch Information

Google addressed this vulnerability in the Android Security Bulletin March 2020. Organizations and users should ensure their Android devices are updated to security patch levels dated 2020-03-01 or later to remediate this vulnerability. Given that this vulnerability is listed in the CISA Known Exploited Vulnerabilities Catalog, immediate patching is critical.

Workarounds

• Restrict installation of applications to trusted sources only (Google Play Store with Play Protect enabled)
• Implement mobile device management (MDM) solutions to enforce security policies
• Limit device access to trusted users to reduce local attack surface
• Consider device replacement for Android devices no longer receiving security updates