CVE-2019-9379 in Android
Summary
by MITRE
In libstagefright, there is a possible resource exhaustion due to a missing bounds check. This could lead to remote denial of service with no additional execution privileges needed. User interaction is needed for exploitation. Product: AndroidVersions: Android-10Android ID: A-124329638
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Analysis
by VulDB Data Team • 09/13/2020
The vulnerability identified as CVE-2019-9379 resides within the libstagefright multimedia framework component of Android operating systems, specifically affecting Android 10 and earlier versions. This issue represents a critical resource exhaustion flaw that stems from inadequate bounds checking mechanisms within the media processing pipeline. The vulnerability manifests when the system processes malformed multimedia files, particularly those containing crafted audio or video content that exceeds expected parameter limits. According to the Android security bulletin, this flaw affects the stagefright media framework which handles various multimedia formats including mp4, 3gp, and other container formats that leverage the underlying libstagefright library for parsing and decoding operations.
The technical root cause of this vulnerability aligns with CWE-129, which describes improper validation of array index bounds, and specifically demonstrates a missing bounds check that allows attackers to manipulate buffer allocation parameters. When a maliciously crafted multimedia file is processed by the stagefright component, the system fails to validate the size parameters of various data structures before allocating memory resources. This oversight enables an attacker to specify excessively large values for buffer sizes or array dimensions, leading to abnormal memory consumption patterns that can exhaust available system resources. The flaw operates at the level of the media parser where it processes headers and metadata of multimedia containers, and the missing validation allows for arbitrary memory allocation requests that can overwhelm system memory pools.
The operational impact of this vulnerability creates a remote denial of service condition that can be triggered without requiring any special privileges or root access. An attacker needs only to convince a victim to open or play a maliciously crafted multimedia file, which typically requires user interaction through opening a file attachment or visiting a webpage containing embedded media. This makes the vulnerability particularly dangerous in mobile environments where users frequently interact with multimedia content from untrusted sources. The exploitation process involves sending a specially crafted media file that causes the libstagefright component to allocate excessive memory resources, potentially leading to system instability, application crashes, or complete system hang conditions that prevent normal device operation. The vulnerability affects the core multimedia processing capabilities of Android devices, making it a significant threat to mobile device usability and reliability.
Mitigation strategies for CVE-2019-9379 should focus on both immediate patch deployment and operational security measures to protect against exploitation. Organizations should prioritize immediate deployment of Android security patches that address the bounds checking deficiencies in libstagefright, with particular attention to Android 10 and earlier versions that remain vulnerable. The recommended approach includes implementing network-level filtering to block suspicious multimedia file types and content, especially those that are commonly used in social engineering attacks. Additionally, users should be educated about the risks of opening multimedia attachments from unknown sources, and mobile device management solutions should enforce strict policies regarding media file handling. Security monitoring should include detection of abnormal memory allocation patterns and unusual network traffic related to multimedia processing, as these could indicate exploitation attempts. The vulnerability also highlights the importance of secure coding practices in mobile frameworks and demonstrates the necessity of comprehensive input validation mechanisms that align with security best practices outlined in the OWASP mobile security project and NIST cybersecurity guidelines for mobile device management.