CVE-2019-2108 in Android
Summary
by MITRE
In ihevcd_ref_list of ihevcd_ref_list.c in Android 10, 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.
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Analysis
by VulDB Data Team • 12/13/2023
The vulnerability identified as CVE-2019-2108 resides within the ihevcd_ref_list component of the Android 10 media processing stack, specifically in the ihevcd_ref_list.c source file. This flaw represents a critical security weakness that affects the hardware-based video decoding functionality implemented in Android devices. The issue manifests as a missing bounds check during reference list processing, which occurs when handling video frames in the H.264 video decoding pipeline. The vulnerability is classified under CWE-129 as an "Improper Validation of Array Index" and demonstrates the classic pattern of insufficient input validation that can lead to memory corruption vulnerabilities.
The technical implementation of this vulnerability stems from the improper handling of reference frame indices within the video decoding process. When processing H.264 video streams, the decoder maintains reference lists that track previously decoded frames for motion compensation operations. The missing bounds check occurs during the validation of reference frame indices, where the code fails to verify that incoming indices fall within the valid range of the reference list array. This allows an attacker to provide maliciously crafted video data that contains out-of-bounds indices, potentially causing the decoder to write data beyond the allocated memory boundaries of the reference list structure. The vulnerability operates at the kernel level within the media framework, making it particularly dangerous as it can be exploited through untrusted video content.
The operational impact of CVE-2019-2108 extends beyond simple memory corruption, as it presents a pathway to remote code execution without requiring elevated privileges. The vulnerability requires user interaction for exploitation, typically through the delivery of malicious video content via email attachments, web downloads, or multimedia messaging services. Once exploited, the out-of-bounds write can corrupt adjacent memory locations, potentially overwriting function pointers, return addresses, or other critical control data structures within the video decoding process. This memory corruption can be leveraged to execute arbitrary code within the context of the media processing service, effectively granting attackers the ability to compromise the device's security posture. The attack vector aligns with ATT&CK technique T1203, "Exploitation for Client Execution," where adversaries leverage software vulnerabilities to execute malicious code on target systems.
Mitigation strategies for this vulnerability must address both the immediate security risk and the broader media processing attack surface. Android device manufacturers should prioritize the deployment of security patches that implement proper bounds checking in the reference list validation logic, ensuring that all indices are validated against the maximum allowable range before being used to access memory locations. The fix should incorporate defensive programming practices that include array boundary checks, input validation, and proper error handling mechanisms. Organizations should also implement network-based security controls such as content filtering and sandboxing of multimedia processing components to limit the potential impact of exploitation attempts. Additionally, user awareness programs should emphasize the importance of avoiding untrusted video content and maintaining up-to-date device firmware to protect against known vulnerabilities in the media processing pipeline.