CVE-2020-0152 in Android
Summary
by MITRE
In avb_vbmeta_image_verify of avb_vbmeta_image.c, there is a possible out of bounds read due to a missing bounds check. This could lead to local information disclosure with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-10Android ID: A-145992159
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Analysis
by VulDB Data Team • 06/12/2020
The vulnerability identified as CVE-2020-0152 resides within the Android operating system's verification mechanism for verified boot components, specifically in the avb_vbmeta_image_verify function located in avb_vbmeta_image.c. This flaw represents a critical security weakness that could potentially allow attackers to extract sensitive information from system memory through an out-of-bounds read condition. The vulnerability manifests when the Android Verified Boot system attempts to validate boot images, which is a fundamental security process that ensures only trusted software executes on the device. The missing bounds check creates an exploitable condition where the system reads memory beyond the intended buffer boundaries, potentially exposing confidential data to unauthorized access.
The technical implementation of this vulnerability stems from inadequate input validation within the Android Verified Boot framework, which operates under the broader context of Android's security architecture. According to CWE-129, this vulnerability maps to an insufficient bounds check, a common class of programming errors that occur when applications fail to validate the size or range of input data before processing it. The flaw exists specifically in how the system handles verification of vbmeta images, which are critical components that contain metadata about the boot process and cryptographic signatures. When the avb_vbmeta_image_verify function processes these images, it fails to properly validate the size of the data being read, allowing for memory access beyond the allocated buffer space.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides a potential pathway for attackers to gather sensitive system information that could aid in further exploitation attempts. An attacker with system execution privileges could leverage this vulnerability to read memory contents that might include cryptographic keys, security tokens, or other confidential data stored in the system's memory space. This information disclosure could ultimately enable more sophisticated attacks such as privilege escalation or bypass of other security mechanisms. The vulnerability's classification as requiring system execution privileges indicates that it cannot be exploited remotely, but rather requires an attacker to already have some level of access to the device, making it particularly concerning for scenarios where device compromise has already occurred.
From an ATT&CK framework perspective, this vulnerability aligns with techniques related to privilege escalation and information gathering, specifically mapping to T1068 for local privilege escalation and T1082 for system information discovery. The vulnerability could be exploited as part of a multi-stage attack where initial access is gained through other means, and this weakness is then leveraged to extract additional information from the compromised system. The Android platform's security model relies heavily on verified boot to ensure system integrity, and this vulnerability undermines that fundamental security mechanism by allowing unauthorized memory access during the boot verification process. The vulnerability affects Android 10 systems and is tracked under Android ID A-145992159, indicating its presence in the Android security patch queue and the recognition by Google's security team of its severity.
Mitigation strategies for CVE-2020-0152 should focus on implementing proper bounds checking in the avb_vbmeta_image_verify function and ensuring that all buffer operations within the verified boot framework are properly validated. System administrators and device manufacturers should prioritize applying the relevant Android security patches that address this vulnerability, as the fix typically involves adding proper input validation to prevent out-of-bounds memory reads. Additionally, organizations should consider implementing memory protection mechanisms such as stack canaries or address space layout randomization to further reduce the exploitability of similar vulnerabilities. The vulnerability highlights the importance of rigorous code review processes for security-critical components and demonstrates the necessity of comprehensive testing for buffer overflow conditions in system-level code that handles cryptographic operations and system integrity verification.