CVE-2018-9396 in Android
Summary
by MITRE • 12/05/2024
In rpc_msg_handler and related handlers of drivers/misc/mediatek/eccci/port_rpc.c, there is a possible out of bounds write due to an incorrect bounds check. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 12/19/2024
The vulnerability identified as CVE-2018-9396 resides within the Mediatek ECCC (Embedded Communication Cluster Controller) driver component, specifically in the rpc_msg_handler function and associated handlers located in drivers/misc/mediatek/eccci/port_rpc.c. This flaw represents a critical security weakness that could enable local privilege escalation, allowing an attacker with system execution privileges to gain elevated access to the underlying system. The vulnerability manifests as an out-of-bounds write condition that occurs due to an improper bounds check implementation within the communication handling mechanisms of the Mediatek embedded system architecture.
The technical root cause of this vulnerability stems from inadequate input validation within the RPC message processing functions. When the system processes incoming messages through the eccci driver interface, the bounds checking logic fails to properly validate the size or length of data being written to memory buffers. This incorrect bounds check creates a scenario where maliciously crafted RPC messages can cause the system to write data beyond the allocated memory boundaries, potentially overwriting critical system structures or code segments. The vulnerability is classified under CWE-129 as an "Improper Validation of Array Index" and specifically relates to improper bounds checking in memory operations. The flaw operates at the kernel level within the Mediatek communication driver, making it particularly dangerous as it can be exploited by any process with system execution privileges.
The operational impact of this vulnerability extends beyond simple memory corruption, as it creates a pathway for local privilege escalation attacks. An attacker who can execute code with system privileges can leverage this out-of-bounds write to modify critical kernel data structures, potentially gaining root access or bypassing security controls within the embedded system. The vulnerability's exploitation requires no user interaction, making it particularly concerning as it can be triggered automatically through system communication channels. This characteristic aligns with ATT&CK technique T1068 which involves exploiting vulnerabilities to gain system-level privileges, and specifically relates to the privilege escalation tactics used in embedded system exploitation frameworks. The attack surface is particularly significant within Mediatek-based devices where this driver is implemented, affecting various mobile and embedded platforms that utilize the Mediatek chipsets.
Mitigation strategies for CVE-2018-9396 should focus on implementing proper bounds checking mechanisms within the affected driver code. The most effective approach involves correcting the validation logic to ensure that all buffer operations properly verify array indices and data lengths before performing memory writes. Security patches should include enhanced input validation that prevents any data from being written beyond the intended memory boundaries, with proper bounds checking implemented at the point of data reception and processing. Additionally, system administrators should ensure that all Mediatek-based devices receive timely security updates and that unnecessary system privileges are not granted to processes that might interact with the affected driver interface. The vulnerability highlights the importance of robust memory safety practices in kernel-level code and underscores the need for comprehensive code reviews focusing on buffer management and input validation within embedded system drivers. Organizations should also implement monitoring systems to detect anomalous communication patterns that might indicate exploitation attempts targeting this specific vulnerability.