CVE-2018-9496 in Android
Summary
by MITRE
In ixheaacd_real_synth_fft_p3 of ixheaacd_esbr_fft.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-9.0 Android ID: A-110769924
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Analysis
by VulDB Data Team • 03/29/2020
The vulnerability identified as CVE-2018-9496 represents a critical out-of-bounds write flaw within the ixheaacd_real_synth_fft_p3 function of the ixheaacd_esbr_fft.c file in the Android audio processing subsystem. This issue resides in the ixheaacd library responsible for handling audio decoding operations, specifically within the enhanced scalable bit rate audio processing component. The flaw manifests when the audio decoder processes malformed input data during the synthesis FFT (Fast Fourier Transform) operations, creating a scenario where memory boundaries are exceeded without proper validation.
The technical implementation of this vulnerability stems from a missing bounds check within the audio processing pipeline where the function fails to validate array indices or buffer limits before writing data to memory locations. This particular function operates within the context of audio signal processing, specifically handling real-valued synthesis operations that transform frequency domain data back into time domain audio signals. When the decoder encounters specially crafted audio data that triggers the faulty code path, it can overwrite adjacent memory locations beyond the allocated buffer boundaries. The vulnerability is particularly dangerous because it occurs during audio decoding operations that are frequently encountered in multimedia applications, making exploitation relatively accessible.
From an operational perspective, this vulnerability presents a significant risk as it enables remote code execution with no additional privileges required for exploitation. The attack vector requires only user interaction through the delivery of malicious audio content, which can be embedded in various multimedia formats including mp3, aac, or other audio files commonly used in Android devices. The lack of privilege escalation requirements means that an attacker can achieve code execution without needing to first compromise the device's security model or gain elevated permissions. This characteristic places the vulnerability at the intersection of remote code execution and privilege escalation concerns, making it particularly attractive to threat actors seeking to compromise Android devices. The Android version affected is specifically Android 9.0, indicating this vulnerability impacts devices running the latest security model at the time of discovery, suggesting potential widespread exposure across the Android ecosystem.
The mitigation strategies for this vulnerability should focus on implementing comprehensive bounds checking mechanisms within the audio processing library, specifically addressing the missing validation in the ixheaacd_real_synth_fft_p3 function. System administrators and device manufacturers should prioritize the deployment of the relevant Android security patches that address this specific memory corruption flaw. Additionally, implementing runtime protections such as stack canaries, address space layout randomization, and memory protection mechanisms can provide defense-in-depth against potential exploitation attempts. Organizations should also consider implementing network-based intrusion detection systems that can identify and block malicious audio content that might trigger this vulnerability. The vulnerability aligns with CWE-129, which describes improper validation of array indices, and represents a clear violation of secure coding practices that should be addressed through comprehensive code review processes and automated static analysis tools. From an ATT&CK framework perspective, this vulnerability maps to techniques involving code injection and privilege escalation, potentially enabling adversaries to establish persistent access to affected Android devices through carefully crafted multimedia content delivery.