CVE-2020-0205 in Android
Summary
by MITRE
In the DaalaBitReader constructor of entropy_decoder.cc, there is a possible out of bounds read due to a missing bounds check. This could lead to remote information disclosure in the media server with no additional execution privileges needed. User interaction is needed for exploitation.Product: AndroidVersions: Android-10Android ID: A-147234020
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Analysis
by VulDB Data Team • 06/12/2020
The vulnerability described in CVE-2020-0205 resides within the DaalaBitReader constructor implementation in the entropy_decoder.cc file of a media processing component. This flaw represents a classic out-of-bounds memory access issue that occurs when the system fails to validate input data boundaries before processing. The vulnerability specifically manifests during the initialization of the bit reader component used for decoding entropy-coded data streams, which is fundamental to various media compression formats including those used in Android's multimedia framework.
The technical nature of this vulnerability stems from insufficient bounds checking mechanisms within the entropy decoding process. When the DaalaBitReader attempts to read data from a bit stream without proper validation of buffer limits, it can access memory locations beyond the allocated buffer boundaries. This missing validation creates a condition where maliciously crafted media files could trigger unauthorized memory access patterns. The vulnerability is classified under CWE-129 as "Improper Validation of Array Index" and falls under the broader category of memory safety issues that can lead to information disclosure or potential code execution.
The operational impact of this vulnerability extends to Android 10 systems where the media server component processes incoming media content. An attacker could exploit this weakness by crafting specially formatted media files that, when processed by the vulnerable media server, would cause the bit reader to access out-of-bounds memory locations. This information disclosure could potentially expose sensitive data from the server's memory space, including cryptographic keys, user credentials, or other confidential information stored in adjacent memory regions. The attack requires only user interaction to deliver the malicious media content, making it particularly dangerous in environments where users might encounter untrusted media files.
From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1566 for Phishing, as it enables remote code execution through malicious media files delivered via email or web-based attacks. The exploitation process would involve preparing a crafted media file that triggers the vulnerable code path when the media server attempts to decode the content. The lack of additional execution privileges required for exploitation makes this vulnerability particularly concerning as it can be leveraged by attackers with minimal privileges. Organizations should implement immediate mitigations including updating to patched versions of Android 10, implementing strict media file validation, and deploying network-based intrusion detection systems to monitor for suspicious media file processing activities. The vulnerability also highlights the importance of proper input validation in multimedia processing pipelines and serves as a reminder of the critical need for bounds checking in low-level bit manipulation code.