CVE-2019-9305 in Android
Summary
by MITRE
In libAACdec, there is a possible out of bounds write due to an integer overflow. This could lead to remote code execution with no additional execution privileges needed. User interaction is needed for exploitation. Product: AndroidVersions: Android-10Android ID: A-112661835
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Analysis
by VulDB Data Team • 09/12/2020
The vulnerability identified as CVE-2019-9305 resides within the libAACdec library component of Android systems, specifically affecting Android 10 and earlier versions. This flaw represents a critical security weakness that stems from improper handling of integer values during audio decoding processes. The vulnerability manifests as an integer overflow condition that can potentially result in out-of-bounds memory writes, creating a pathway for malicious code execution. The issue is particularly concerning because it requires no additional privileges for exploitation, making it accessible to attackers who can remotely deliver malicious audio content. The Android ID A-112661835 specifically tracks this vulnerability within Google's internal tracking systems, indicating its severity and the need for immediate remediation.
The technical flaw occurs within the Advanced Audio Coding (AAC) decoding functionality where integer overflow conditions are not properly validated before memory allocation operations. When processing malformed AAC audio files, the decoder fails to correctly handle integer arithmetic that results in buffer size calculations exceeding maximum allowable values. This overflow condition causes subsequent memory writes to occur beyond the intended buffer boundaries, potentially overwriting adjacent memory regions. The vulnerability is classified under CWE-190 as an integer overflow condition, which is a well-documented weakness that frequently leads to memory corruption issues. The flaw demonstrates characteristics consistent with memory safety vulnerabilities that are commonly exploited in the ATT&CK framework under the technique T1059.007 for command and scripting interpreter, where remote code execution can be achieved through memory corruption attacks.
The operational impact of this vulnerability extends beyond simple audio processing failures, as it can be leveraged for full system compromise. Attackers can craft malicious AAC files that when played through affected Android devices will trigger the integer overflow, leading to arbitrary code execution. The requirement for user interaction means that the attack vector typically involves social engineering or phishing campaigns where users are tricked into opening malicious audio content. This could occur through email attachments, messaging applications, or malicious websites that deliver the crafted audio files. The remote execution capability makes this vulnerability particularly dangerous as it allows attackers to compromise devices without physical access or network privileges. The vulnerability affects all Android 10 devices and potentially earlier versions that utilize the same libAACdec library, creating a widespread attack surface across numerous mobile devices.
Mitigation strategies for CVE-2019-9305 should prioritize immediate system updates from Google and device manufacturers, as the vulnerability was addressed through security patches released as part of Android security updates. Organizations and individuals should ensure their devices are running the latest security patches, particularly those released in the February 2019 Android security bulletin. Network administrators should consider implementing content filtering measures to prevent the delivery of potentially malicious audio files, especially in enterprise environments where device management is critical. The vulnerability highlights the importance of robust input validation and memory safety practices in multimedia decoding libraries, which aligns with security best practices outlined in the OWASP Top Ten and NIST cybersecurity guidelines. Device users should exercise caution when opening audio files from untrusted sources and maintain awareness of social engineering tactics that might exploit this vulnerability. Additionally, security monitoring should be implemented to detect unusual audio processing activities that might indicate exploitation attempts.