CVE-2018-9535 in Android
Summary
by MITRE
In ixheaacd_reset_acelp_data_fix of ixheaacd_lpc.c there is a possible out of bounds write due to a missing bounds check. This could lead to remote code execution with no additional execution privileges needed. User interaction is needed for exploitation. Product: Android. Versions: Android-9. Android ID: A-112858010
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Analysis
by VulDB Data Team • 04/13/2020
The vulnerability identified as CVE-2018-9535 represents a critical out-of-bounds write flaw within the audio decoding component of Android systems. This issue resides in the ixheaacd_reset_acelp_data_fix function located in the ixheaacd_lpc.c source file, which forms part of the audio processing pipeline responsible for handling ACELP (Algebraic Code Excited Linear Prediction) data. The flaw manifests when the system fails to perform proper bounds checking before writing data to memory locations, creating a potential pathway for malicious code execution. The vulnerability specifically affects Android 9.0 systems and is tracked under Android ID A-112858010, indicating its significance within the Android security framework.
The technical nature of this vulnerability stems from insufficient input validation within the audio processing subsystem, particularly when handling compressed audio data streams. When the ixheaacd_reset_acelp_data_fix function processes audio parameters, it does not adequately verify array boundaries before performing memory writes. This missing bounds check creates an exploitable condition where an attacker could craft malicious audio data that, when processed by the vulnerable decoder, causes data to be written beyond the allocated memory buffer. The flaw operates at the intersection of audio codec processing and memory management, making it particularly dangerous as it can be triggered through normal audio playback operations.
The operational impact of this vulnerability extends beyond simple data corruption, presenting a severe remote code execution risk that could be leveraged by attackers without requiring elevated privileges. The necessity for user interaction to exploit this vulnerability suggests that a malicious audio file or stream would need to be presented to the user, who would then need to play it through the affected Android system. This could occur through various attack vectors including malicious email attachments, web-based audio content, or compromised media files downloaded from untrusted sources. The vulnerability's classification as a remote code execution flaw means that successful exploitation could allow attackers to execute arbitrary code on the target device, potentially leading to full system compromise and data theft.
Security professionals should note that this vulnerability aligns with CWE-787 (Out-of-bounds Write) and represents a classic example of how memory safety issues can create severe exploitation opportunities. The ATT&CK framework would categorize this vulnerability under T1059 (Command and Scripting Interpreter) and potentially T1068 (Exploitation for Privilege Escalation) if exploitation leads to elevated privileges. The fact that this vulnerability requires user interaction but can result in remote code execution aligns with attack patterns described in the Android security model where user-facing components like media players are prime targets for exploitation. Organizations should prioritize patching affected Android 9.0 systems and consider implementing additional security measures such as audio content filtering and sandboxing to mitigate the risk of exploitation.
Mitigation strategies for CVE-2018-9535 should focus on immediate system updates and ongoing monitoring of audio processing components. Android users should ensure their devices are updated to the latest security patches released by Google, which would include fixes for this specific vulnerability. System administrators should also consider implementing network-level controls to prevent the delivery of potentially malicious audio content and monitor for unusual audio processing activity. The vulnerability highlights the importance of robust bounds checking in audio and multimedia processing components, emphasizing the need for comprehensive security testing of media handling code. Additionally, organizations should maintain awareness of similar vulnerabilities in other audio codecs and multimedia libraries, as this flaw represents a broader class of issues that can affect multimedia processing systems across various platforms and operating systems.