CVE-2020-0323 in Android
Summary
by MITRE
In libavb, there is a possible out of bounds read due to a missing bounds check. This could lead to local information disclosure with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-11Android ID: A-146516087
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 09/18/2020
The vulnerability identified as CVE-2020-0323 resides within the Android Verified Boot (AVB) library component, specifically affecting Android 11 systems. This issue represents a critical security flaw in the verification process that governs how Android devices validate system images and boot components. The vulnerability manifests as a missing bounds check within the libavb library, which is responsible for implementing the Android Verified Boot mechanism that ensures device integrity and prevents unauthorized modifications to the operating system.
The technical flaw constitutes an out-of-bounds read condition that occurs when the libavb library processes certain input data structures without proper validation of array boundaries. This missing bounds check allows an attacker to potentially access memory locations beyond the intended data buffer, leading to information disclosure. The vulnerability is particularly concerning because it can be exploited locally without requiring any additional privileges or user interaction, making it accessible to any process running on the device with minimal attack surface requirements.
From an operational impact perspective, this vulnerability compromises the fundamental security assurances provided by Android Verified Boot. The local information disclosure could potentially expose sensitive cryptographic keys, boot parameters, or other confidential data that the AVB system is designed to protect. Attackers could leverage this information to bypass security measures, potentially enabling more sophisticated attacks such as boot hijacking or privilege escalation. The vulnerability affects the integrity verification process that occurs during device boot, meaning it could be exploited during critical system initialization phases.
The exploitability of this vulnerability aligns with ATT&CK technique T1552.001 for unsecured credentials and T1068 for local privilege escalation, as it provides a mechanism for accessing protected system information. According to CWE classification, this represents a CWE-129: Improper Validation of Array Index vulnerability, where the system fails to validate that array indices are within acceptable ranges. The lack of user interaction requirement makes this vulnerability particularly dangerous as it can be exploited silently in the background, potentially going undetected by standard security monitoring systems.
Mitigation strategies should focus on immediate patch deployment through Android security updates, as the vulnerability affects core system components. Organizations should implement comprehensive monitoring for unauthorized system modifications and establish robust incident response procedures to detect potential exploitation attempts. The fix typically involves implementing proper bounds checking mechanisms within the libavb library to validate all array access operations before memory dereferencing occurs. Additionally, regular security audits of system libraries and proactive vulnerability scanning should be conducted to identify similar issues in other security-critical components.