CVE-2021-0414 in MT5522
Summary
by MITRE • 10/25/2021
In flv extractor, there is a possible out of bounds read due to a heap buffer overflow. This could lead to local information disclosure with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS05561384; Issue ID: ALPS05561384.
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Analysis
by VulDB Data Team • 10/30/2021
The vulnerability identified as CVE-2021-0414 resides within the flv extractor component of a mobile operating system, specifically affecting Android-based devices. This issue represents a critical heap buffer overflow condition that manifests as an out-of-bounds read operation, fundamentally compromising the memory integrity of the affected system. The flaw originates from insufficient input validation and boundary checking within the flv file parsing mechanism, which processes flash video files commonly used in multimedia applications. The vulnerability is particularly concerning as it operates entirely within the confines of the operating system's multimedia processing framework without requiring any specialized privileges or user interaction for exploitation.
The technical implementation of this vulnerability stems from improper handling of heap memory allocation when processing flv format files. When the flv extractor encounters malformed or specially crafted input data, it fails to properly validate the size and structure of the buffer before attempting to read beyond its allocated boundaries. This condition creates a scenario where the system attempts to access memory locations that are either uninitialized or belong to other processes, potentially exposing sensitive data stored in adjacent memory segments. The out-of-bounds read operation can inadvertently retrieve confidential information such as cryptographic keys, user credentials, or application data that resides in memory adjacent to the vulnerable buffer, making this a significant information disclosure risk.
The operational impact of CVE-2021-0414 extends beyond simple data exposure, as it represents a stealthy attack vector that can be leveraged for reconnaissance purposes without requiring any user interaction or elevated privileges. Attackers can craft malicious flv files that trigger the buffer overflow condition when processed by the system's multimedia framework, potentially leading to the disclosure of sensitive information stored in memory. The vulnerability's classification as a local information disclosure means that an attacker must only have the ability to place a malicious file on the device, which can be achieved through various attack vectors including phishing, compromised applications, or malicious website content that triggers automatic download and processing. This makes the vulnerability particularly dangerous in environments where users frequently download content from untrusted sources.
Mitigation strategies for this vulnerability primarily focus on patch management and system hardening approaches. The vendor has addressed this issue through patch ID ALPS05561384, which implements proper boundary checking and input validation within the flv extractor component. System administrators and device users should prioritize immediate patch deployment to protect against exploitation attempts. Additional defensive measures include implementing strict file type validation for multimedia content, deploying application whitelisting policies to restrict execution of untrusted flv files, and monitoring for unusual memory access patterns that might indicate exploitation attempts. From a security architecture perspective, this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and represents a typical example of how insufficient input validation can lead to memory corruption vulnerabilities. The ATT&CK framework categorizes this type of vulnerability under privilege escalation and defense evasion techniques, as it enables attackers to gain access to information that would otherwise remain protected within the system's memory space, potentially serving as a stepping stone for more sophisticated attacks.