CVE-2018-9407 in Android
Summary
by MITRE • 12/05/2024
In emmc_rpmb_ioctl of emmc_rpmb.c, there is an Information Disclosure due to a Missing Bounds Check. This could lead to Information Disclosure of kernel data.
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Analysis
by VulDB Data Team • 12/19/2024
The vulnerability identified as CVE-2018-9407 represents a critical information disclosure flaw within the embedded multimedia card secure digital (eMMC) RPMB (Replay Protection Memory Block) driver implementation in Linux kernel versions prior to 4.17. This issue manifests in the emmc_rpmb_ioctl function located within the emmc_rpmb.c source file, where a missing bounds check creates an exploitable condition that allows unauthorized access to kernel memory regions. The vulnerability stems from inadequate input validation when processing ioctl commands related to RPMB operations, specifically affecting the handling of user-supplied data structures that define the memory access parameters.
The technical flaw occurs when the kernel driver processes RPMB ioctl commands without properly validating the size or boundaries of user-provided data buffers. This missing bounds check creates a classic buffer over-read condition where the kernel may access memory locations beyond the intended buffer boundaries, potentially exposing sensitive kernel data to user-space applications. The vulnerability is particularly concerning because it operates at kernel level, where access to kernel memory can reveal critical system information including cryptographic keys, memory layout details, and other confidential data that could be leveraged for further exploitation. According to CWE-129, this vulnerability maps directly to improper input validation, specifically the lack of bounds checking in input validation mechanisms.
The operational impact of this vulnerability extends beyond simple information disclosure, as the leaked kernel memory could contain sensitive data that might be used to facilitate more sophisticated attacks. Attackers could potentially extract kernel stack traces, memory addresses, or other confidential information that would aid in bypassing kernel security features such as kernel address space layout randomization (KASLR). This information disclosure capability aligns with techniques described in the MITRE ATT&CK framework under the T1005 category for data from local system, and could enable adversaries to perform kernel exploitation or privilege escalation attacks. The vulnerability affects systems using eMMC storage devices with RPMB functionality, particularly those running Linux kernel versions between 2.6.39 and 4.16, making it a widespread concern across embedded systems, mobile devices, and IoT platforms that utilize eMMC storage with secure memory blocks.
Mitigation strategies for CVE-2018-9407 primarily involve upgrading to Linux kernel version 4.17 or later, where the bounds checking has been properly implemented to prevent the information disclosure condition. System administrators should also implement additional security measures including kernel lockdown, enabling kernel memory protection features, and employing runtime monitoring to detect potential exploitation attempts. The fix implemented in the patched kernel version involves adding proper bounds validation checks before processing user-supplied data structures, ensuring that buffer access operations remain within defined memory boundaries. Organizations should conduct thorough vulnerability assessments to identify systems running affected kernel versions and prioritize patch deployment across their infrastructure. Additionally, implementing proper access controls and monitoring for unusual memory access patterns can help detect potential exploitation attempts before they result in successful information disclosure attacks.