CVE-2021-0573 in Android
Summary
by MITRE • 08/17/2021
In asf extractor, there is a possible out of bounds write due to a missing bounds check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android SoCAndroid ID: A-187231635
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Analysis
by VulDB Data Team • 08/19/2021
The vulnerability identified as CVE-2021-0573 resides within the asf extractor component of Android operating systems, representing a critical security flaw that enables local privilege escalation without requiring additional execution privileges or user interaction. This issue manifests as an out-of-bounds write condition that occurs when the system fails to properly validate input data boundaries during processing of asf files. The vulnerability affects Android SoC implementations and has been assigned Android ID A-187231635, indicating its severity and impact scope across various device implementations. The flaw exists in the media processing pipeline where asf files are parsed and extracted, creating a potential attack vector for malicious actors who can leverage this weakness to elevate their privileges locally.
The technical root cause of this vulnerability stems from a missing bounds check within the asf extractor's data processing logic. When the system attempts to parse asf media files, it fails to validate the size and boundaries of incoming data structures before writing to memory locations. This allows an attacker to craft specially malformed asf files that can cause the extractor to write data beyond the allocated memory buffer. The absence of proper input validation creates an exploitable condition where memory corruption occurs, potentially allowing attackers to overwrite critical system memory regions. This type of vulnerability falls under CWE-129, which specifically addresses improper validation of array indices, and more broadly aligns with CWE-787, representing out-of-bounds write conditions that can lead to arbitrary code execution or privilege escalation.
The operational impact of CVE-2021-0573 extends beyond simple local privilege escalation, as it represents a significant threat to Android device security. Attackers who can successfully exploit this vulnerability gain the ability to execute code with elevated privileges, potentially accessing sensitive system resources, modifying critical files, or establishing persistent backdoors. The lack of requirement for user interaction makes this particularly dangerous as it can be exploited automatically when the device processes asf media files, which may occur during normal device operation or when users simply connect external storage devices. This vulnerability directly maps to ATT&CK technique T1068, which covers local privilege escalation, and T1548.001, covering abuse of privileges through local escalation techniques. The exploitation process requires minimal prerequisites, making it an attractive target for attackers seeking to compromise Android devices without requiring complex attack chains or user interaction.
Mitigation strategies for this vulnerability should focus on immediate patch deployment through official Android security updates, as the issue affects core system components that require comprehensive fixes. Device manufacturers should prioritize rolling out security patches to affected Android versions, particularly targeting the Android SoC implementations that are vulnerable. Additionally, system administrators should consider implementing runtime monitoring solutions that can detect anomalous memory access patterns or unauthorized privilege escalation attempts. The vulnerability can be addressed through enhanced bounds checking mechanisms within the asf extractor component, proper input validation procedures, and memory protection features such as stack canaries or address space layout randomization. Organizations should also implement network segmentation and access controls to limit potential exploitation vectors, while monitoring for suspicious file processing activities that might indicate attempted exploitation. Regular security assessments and vulnerability scanning should be conducted to identify any similar boundary checking issues within other media processing components, as this represents a pattern of vulnerabilities that could affect other file format parsers within the Android ecosystem.