CVE-2017-13179 in Android
Summary
by MITRE
In the ihevcd_allocate_static_bufs and ihevcd_create functions of SoftHEVC, there is a possible out-of-bounds write due to a use after free. Both ps_codec_obj and ps_create_op->s_ivd_create_op_t.pv_handle point to the same memory and ps_codec_obj could be freed without clearing ps_create_op->s_ivd_create_op_t.pv_handle. This could lead to remote code execution as a privileged process with no additional execution privileges needed. User interaction is not needed for exploitation. Product: Android. Versions: 6.0.1, 7.0, 7.1.1, 7.1.2, 8.0, 8.1. Android ID: A-66969193.
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Analysis
by VulDB Data Team • 01/28/2021
The vulnerability identified as CVE-2017-13179 resides within the SoftHEVC decoder implementation in Android systems, specifically affecting versions 6.0.1 through 8.1. This issue manifests as a use-after-free condition that can potentially lead to remote code execution. The flaw occurs in the ihevcd_allocate_static_bufs and ihevcd_create functions where memory management practices create dangerous scenarios for memory access. The core problem emerges from the improper handling of memory pointers where both ps_codec_obj and ps_create_op->s_ivd_create_op_t.pv_handle reference identical memory locations. When ps_codec_obj is freed, the pv_handle pointer within ps_create_op remains pointing to the now-freed memory region, creating a situation where subsequent operations might attempt to write data to memory that has already been deallocated.
This vulnerability represents a classic use-after-free scenario that maps to CWE-416, which specifically addresses the use of freed memory conditions. The operational impact of this flaw is severe as it allows for arbitrary code execution when a privileged process accesses the corrupted memory, requiring no additional privileges or user interaction for exploitation. The attack vector is particularly concerning because it can be triggered remotely without any user intervention, making it an ideal candidate for automated exploitation. The Android security model allows for such vulnerabilities to be leveraged by malicious actors who can craft specially formatted HEVC video content that, when processed by the vulnerable decoder, triggers the memory corruption.
The technical exploitation of this vulnerability follows a well-defined pattern that aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation. When the SoftHEVC decoder processes malicious input, the freed memory location becomes available for reuse, and subsequent writes to this location can overwrite critical data structures or function pointers. This memory corruption can be manipulated to redirect execution flow to attacker-controlled code, particularly when the freed memory is reallocated for subsequent operations within the same process context. The vulnerability's impact is amplified by the fact that the affected decoder is part of the Android multimedia framework, which is frequently accessed during media processing operations.
Mitigation strategies for this vulnerability require immediate system updates and patches provided by Google through the Android security bulletin. Organizations should prioritize patching all affected Android versions to prevent exploitation, as the vulnerability exists at the system level and affects core multimedia processing capabilities. Additionally, implementing memory safety checks and using modern memory management techniques such as address space layout randomization and stack canaries can help reduce the exploitability of similar issues. The vulnerability demonstrates the importance of proper memory management practices in security-critical components and highlights how seemingly minor pointer management errors can result in severe remote code execution capabilities. System administrators should also consider implementing network segmentation and monitoring for suspicious media processing activities that might indicate exploitation attempts.