CVE-2021-0402 in Android
Summary
by MITRE • 02/27/2021
In jpeg, there is a possible out of bounds write due to improper input validation. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation. Product: Android; Versions: Android-11; Patch ID: ALPS05433311.
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Analysis
by VulDB Data Team • 03/05/2021
The vulnerability identified as CVE-2021-0402 resides within the jpeg component of Android systems, specifically affecting Android 11 implementations. This issue represents a critical security flaw that stems from inadequate input validation mechanisms within the image processing pipeline. The vulnerability manifests as a possible out of bounds write condition that occurs during the parsing of jpeg image files, creating a pathway for malicious actors to exploit the system's memory management functions. The flaw exists in the way the system handles malformed jpeg data structures, particularly when processing certain metadata or image compression parameters that exceed expected boundaries. This type of vulnerability falls under the CWE-129 category of Improper Validation of Array Index, which specifically addresses situations where input validation fails to properly check array indices or buffer boundaries.
The operational impact of CVE-2021-0402 extends beyond simple data corruption, as it provides a potential pathway for local privilege escalation attacks. An attacker who successfully exploits this vulnerability can achieve system execution privileges, effectively gaining control over the Android device's core operations. The vulnerability's exploitation does not require user interaction, making it particularly dangerous as it can be triggered automatically when the system processes malicious jpeg files. This characteristic aligns with ATT&CK technique T1068 which covers the use of local privilege escalation techniques, and T1059 which covers execution through command and scripting interpreters. The vulnerability's presence in the jpeg processing component means that any application or system service that handles jpeg images could potentially be exploited, including image viewers, email clients, and file managers that automatically process image attachments.
The patch referenced as ALPS05433311 specifically addresses the input validation gaps within the jpeg parser's memory allocation and boundary checking mechanisms. This fix implements proper bounds checking for array indices and buffer sizes during jpeg file processing, ensuring that all input data is validated against expected parameter ranges before any memory operations occur. The mitigation strategy involves strengthening the input validation routines within the jpeg decoding library, particularly focusing on the handling of variable length fields and compressed data structures. Organizations should prioritize applying this patch immediately to all affected Android 11 devices, as the vulnerability's automatic exploitation capability means that devices remain at risk even when users are not actively interacting with potentially malicious content. The vulnerability's classification as a local privilege escalation issue also means that any application with access to the device's image processing capabilities could potentially serve as an attack vector, making comprehensive patch management essential for maintaining device security.