CVE-2018-9473 in Android
Summary
by MITRE
In ihevcd_parse_sei_payload of ihevcd_parse_headers.c, there is a possible out-of-bounds write due to an integer overflow. This could lead to remote code execution with no additional execution privileges needed. User interaction is needed for exploitation. Product: Android Versions: Android-8.0 Android ID: A-65484460
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Analysis
by VulDB Data Team • 03/29/2020
The vulnerability identified as CVE-2018-9473 represents a critical out-of-bounds write condition within the ihevcd video decoder component of Android systems. This flaw exists in the ihevcd_parse_sei_payload function located in the ihevcd_parse_headers.c source file, where an integer overflow occurs during the processing of video stream headers. The vulnerability specifically affects Android 8.0 implementations and is tracked under Android ID A-65484460. The integer overflow manifests when the decoder processes specific sequences of video data containing SEI (Supplemental Enhancement Information) payloads, which are used to convey additional metadata within video streams.
The technical nature of this vulnerability stems from inadequate input validation and arithmetic overflow handling within the video parsing logic. When processing maliciously crafted video content, the integer overflow causes the decoder to write data beyond the allocated memory boundaries, potentially corrupting adjacent memory regions. This memory corruption can be exploited to overwrite critical program structures, function pointers, or executable code segments. The vulnerability's remote code execution potential arises because the decoder processes video content from untrusted sources such as network streams, email attachments, or downloaded media files without proper boundary checks. The attack requires user interaction to initiate the exploitation process, typically through the automatic playback of malicious media content or when a user opens a specially crafted video file.
From an operational perspective, this vulnerability presents a significant risk to Android 8.0 devices as it allows attackers to execute arbitrary code with the privileges of the video decoder process. The lack of additional execution privileges required for exploitation makes this particularly dangerous, as the attacker does not need to escalate privileges from a lower-privilege user account. The vulnerability's impact extends beyond individual device compromise, as it can be leveraged for broader attacks including information theft, persistent backdoor installation, or as a stepping stone for further system compromise. The SEI payload processing mechanism is commonly used in video streaming applications, making this vulnerability particularly prevalent in environments where users frequently consume media content from untrusted sources.
The vulnerability aligns with CWE-190, which describes integer overflow conditions, and maps to ATT&CK technique T1059.007 for command and scripting interpreter. The exploitation process typically follows the pattern of crafting malicious video content with specifically designed SEI payloads that trigger the integer overflow during parsing. Mitigation strategies should focus on input validation improvements, memory boundary checks, and proper integer arithmetic handling within the video decoding pipeline. Android security patches addressing this vulnerability typically include enhanced bounds checking in the ihevcd_parse_headers.c file, proper integer overflow detection mechanisms, and stricter validation of SEI payload parameters. Organizations should prioritize immediate patch deployment and consider network-based filtering of suspicious video content until full remediation is achieved. The vulnerability demonstrates the critical importance of robust input validation in multimedia processing components and highlights the need for comprehensive security testing of media handling libraries in mobile operating systems.