CVE-2015-9218 in Android
Summary
by MITRE
In Android before 2018-04-05 or earlier security patch level on Qualcomm Snapdragon Mobile and Snapdragon Wear MSM8909W, SD 210/SD 212/SD 205, SD 400, SD 410/12, SD 425, SD 427, SD 430, SD 435, SD 450, SD 625, SD 650/52, SD 800, SD 808, SD 810, SD 820, SD 835, SD 845, SDM630, SDM636, SDM660, and Snapdragon_High_Med_2016, when processing bad HEVC clips, the DPB fills, and with no error handling for DPB being full, a hang occurs.
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Analysis
by VulDB Data Team • 01/26/2020
The vulnerability identified as CVE-2015-9218 represents a critical flaw in Qualcomm's Snapdragon mobile chipsets that affects Android devices released prior to the 2018-04-05 security patch level. This issue specifically manifests in the handling of HEVC (H.265) video codec processing within the decoder's decoding process buffer, where the system fails to properly manage buffer overflow conditions during video frame processing. The vulnerability stems from inadequate error handling mechanisms that govern how the decoder manages its internal frame buffer when encountering malformed or malicious HEVC video content, creating a scenario where the system becomes unresponsive and enters a permanent hang state.
The technical implementation of this vulnerability involves the Dynamic Picture Buffer (DPB) management within the hardware-level video decoder component of Qualcomm's Snapdragon processors. When processing malformed HEVC video clips, the decoder attempts to fill the DPB with video frames without proper validation of buffer capacity limits. This flaw creates a condition where the DPB reaches its maximum capacity and cannot accommodate additional frames, yet the system lacks proper error handling routines to detect this overflow condition and respond appropriately. The absence of error detection mechanisms means that when the DPB becomes full, the system cannot gracefully handle the overflow condition, resulting in a complete system hang that prevents normal device operation.
This vulnerability presents significant operational impact across a wide range of mobile devices, particularly those utilizing Qualcomm's Snapdragon 800, 810, 820, 835, 845, and various SD series processors. The attack surface extends to any device running Android with vulnerable Qualcomm chipsets that process HEVC video content, including but not limited to video streaming applications, multimedia messaging services, and any application that handles video decoding. The hang condition created by this vulnerability can persist until device reboot, effectively rendering the device unusable for the duration of the hang, which could be exploited by adversaries to create denial-of-service conditions or potentially as a precursor to more sophisticated attacks.
The vulnerability aligns with CWE-129, which addresses improper validation of array indices, and CWE-362, which covers concurrent execution using shared data without proper synchronization. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, specifically the technique involving system shutdown/reboot, and could potentially be leveraged for T1566.001, the technique involving phishing with malicious attachments. The lack of proper input validation and error handling in the DPB management system creates a vector for attackers to craft malicious HEVC content that triggers the hang condition, potentially enabling persistent denial-of-service attacks against target devices.
The recommended mitigations for this vulnerability include applying the latest security patches from device manufacturers, which typically involve firmware updates that enhance the error handling mechanisms within the Qualcomm video decoder component. Additionally, system administrators should implement network-based filtering to block HEVC content from untrusted sources and consider device-level restrictions on video processing capabilities for applications that do not require HEVC support. Regular security assessments of mobile device management policies should include verification of patch compliance and monitoring for potential exploitation attempts. Organizations should also consider implementing device monitoring solutions that can detect and alert on unusual system hang patterns that may indicate exploitation of this vulnerability, as the hang condition may be difficult to distinguish from legitimate system issues without proper monitoring protocols in place.