CVE-2017-8069 in Linux
Summary
by MITRE
drivers/net/usb/rtl8150.c in the Linux kernel 4.9.x before 4.9.11 interacts incorrectly with the CONFIG_VMAP_STACK option, which allows local users to cause a denial of service (system crash or memory corruption) or possibly have unspecified other impact by leveraging use of more than one virtual page for a DMA scatterlist.
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Analysis
by VulDB Data Team • 12/02/2022
The vulnerability identified as CVE-2017-8069 resides within the Linux kernel's network driver implementation specifically in the rtl8150.c file which manages Realtek RTL8150 USB network adapters. This flaw manifests in kernel versions 4.9.x prior to 4.9.11 and represents a critical issue that affects systems utilizing the CONFIG_VMAP_STACK kernel configuration option. The vulnerability stems from improper handling of DMA scatterlists when multiple virtual pages are involved, creating a scenario where kernel memory structures become corrupted or system stability is compromised.
The technical root cause of this vulnerability lies in the interaction between the USB network driver and the kernel's virtual memory management system when CONFIG_VMAP_STACK is enabled. When this configuration option is active, the kernel allocates stack memory using virtual memory mapping techniques that can span multiple virtual pages. The rtl8150.c driver fails to properly account for this memory layout when processing DMA operations, particularly when dealing with scatterlist structures that may require memory spanning across multiple virtual pages. This mismanagement creates opportunities for memory corruption through improper pointer arithmetic or buffer boundary violations during DMA transfer operations.
The operational impact of this vulnerability extends beyond simple system crashes to potentially enable more sophisticated attacks. Local users with access to the system can exploit this weakness to either induce system crashes through memory corruption or potentially achieve more severe consequences including privilege escalation or information disclosure. The vulnerability's nature as a denial of service condition means that attackers can repeatedly trigger the flaw to destabilize systems running affected kernel versions, making it particularly dangerous in production environments where system uptime is critical. The memory corruption aspect introduces uncertainty regarding the full scope of potential impacts, as corrupted memory could lead to unpredictable system behavior or even allow for code execution under certain conditions.
This vulnerability aligns with CWE-121 and CWE-122 categories from the Common Weakness Enumeration, specifically addressing issues related to buffer overflow conditions and improper handling of memory boundaries in kernel space operations. From an ATT&CK framework perspective, this vulnerability maps to T1068 (Local Privilege Escalation) and T1499 (Endpoint Denial of Service) techniques, as it provides a path for local users to either crash systems or potentially escalate privileges through memory corruption. The attack surface is particularly concerning for embedded systems, servers, and virtualized environments where USB network adapters are commonly used and where kernel memory management is critical for system stability.
Mitigation strategies for CVE-2017-8069 primarily involve upgrading to kernel versions 4.9.11 or later where the issue has been resolved through proper handling of DMA scatterlist operations in conjunction with virtual memory mapping. System administrators should also consider disabling the CONFIG_VMAP_STACK option if the specific functionality is not required, though this may impact other kernel features. Additionally, monitoring systems for unusual memory allocation patterns or kernel crashes can help detect exploitation attempts. Organizations should conduct thorough testing of kernel updates in controlled environments before deployment to ensure compatibility with existing hardware configurations and network infrastructure. The vulnerability underscores the importance of proper kernel memory management practices and the need for comprehensive testing of driver interactions with advanced kernel features.