CVE-2018-9530 in Android
Summary
by MITRE
In ixheaacd_tns_ar_filter_dec of ixheaacd_aac_tns.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-112609715
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Analysis
by VulDB Data Team • 04/13/2020
The vulnerability identified as CVE-2018-9530 represents a critical out-of-bounds write flaw within the Android media processing subsystem, specifically affecting the ixheaacd_tns_ar_filter_dec function in the ixheaacd_aac_tns.c source file. This issue resides in the Advanced Audio Coding (AAC) decoder component that handles audio data processing for Android devices. The flaw stems from the absence of proper bounds checking mechanisms when processing temporal noise shaping parameters, which are essential for audio compression and decompression operations. The vulnerability affects Android 9.0 systems and is tracked under Android ID A-112609715, indicating its classification as a significant security concern requiring immediate attention.
The technical implementation of this vulnerability occurs during the temporal noise shaping process within the AAC decoder where the system attempts to write data to memory locations without validating whether the destination addresses fall within acceptable bounds. This missing validation creates an exploitable condition where an attacker can craft malicious audio files that, when processed by the affected decoder, cause the system to write beyond allocated memory regions. The flaw specifically manifests when the decoder encounters malformed temporal noise shaping data structures that contain invalid indices or parameters. According to CWE-129, this represents an implementation weakness where insufficient input validation leads to buffer overflows, while the ATT&CK framework categorizes this under T1068 for exploit development through local privilege escalation opportunities.
The operational impact of this vulnerability extends beyond simple memory corruption, as it enables remote code execution capabilities without requiring elevated privileges or user interaction beyond the initial exploitation vector. Attackers can potentially deliver malicious audio content through various channels including email attachments, web downloads, or media streaming services, making this a particularly dangerous flaw for widespread exploitation. The requirement for user interaction indicates that the malicious content must be consumed by the target system, typically through media playback applications or automatic processing of downloaded content. This makes the vulnerability particularly concerning for mobile environments where users frequently interact with multimedia content from untrusted sources, and the remote execution capability means attackers can potentially gain full control over affected devices without physical access or additional attack vectors.
Mitigation strategies for CVE-2018-9530 should focus on immediate patch deployment through official Android security updates, which typically include enhanced bounds checking mechanisms and input validation routines for the affected AAC decoder components. Organizations should implement network-level restrictions to prevent unauthorized media content delivery and ensure that all audio processing applications undergo rigorous security testing for input validation. The fix should incorporate defensive programming practices including array boundary checks, use of safe string handling functions, and comprehensive parameter validation before memory operations. Additionally, system administrators should monitor for any suspicious media processing activities and maintain updated security configurations that limit the attack surface for multimedia processing components, while also preparing incident response procedures for potential exploitation attempts targeting this specific vulnerability class.