CVE-2017-18222 in Linux
Summary
by MITRE
In the Linux kernel before 4.12, Hisilicon Network Subsystem (HNS) does not consider the ETH_SS_PRIV_FLAGS case when retrieving sset_count data, which allows local users to cause a denial of service (buffer overflow and memory corruption) or possibly have unspecified other impact, as demonstrated by incompatibility between hns_get_sset_count and ethtool_get_strings.
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Analysis
by VulDB Data Team • 09/14/2025
The vulnerability identified as CVE-2017-18222 resides within the Linux kernel version 4.12 and earlier, specifically affecting the Hisilicon Network Subsystem (HNS) implementation. This issue manifests as a critical flaw in how the subsystem handles sset_count data retrieval operations, creating a scenario where local users can exploit the system through buffer overflow conditions. The root cause stems from the incomplete implementation of the ETH_SS_PRIV_FLAGS case within the HNS network subsystem, which fails to properly account for this specific flag category during string set count operations.
The technical exploitation of this vulnerability occurs through the incompatibility between the hns_get_sset_count function and the ethtool_get_strings functionality. When ethtool attempts to retrieve string set information from the HNS driver, the subsystem does not adequately handle the private flags enumeration case, leading to improper memory management and buffer overflow conditions. This flaw allows attackers to manipulate the kernel's memory structures through controlled inputs, potentially resulting in system instability and denial of service conditions. The vulnerability specifically targets the network subsystem's string handling mechanisms, where the missing ETH_SS_PRIV_FLAGS case causes the driver to either undercount or overcount available string sets, creating memory corruption scenarios.
From an operational impact perspective, this vulnerability presents significant risks to system availability and stability. Local users can leverage this flaw to trigger buffer overflows that may result in kernel panics, system crashes, or more subtle memory corruption issues that could persist and degrade system performance over time. The potential for unspecified other impacts suggests that attackers might be able to escalate privileges or achieve additional system compromise beyond simple denial of service. This vulnerability particularly affects systems utilizing Hisilicon network hardware, making organizations with such infrastructure especially vulnerable to exploitation. The local privilege requirement means that while exploitation requires user-level access, the potential for system-wide impact makes this a serious concern for system administrators.
The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and demonstrates characteristics consistent with CWE-125, representing out-of-bounds read conditions. From an ATT&CK framework perspective, this vulnerability maps to T1068, which covers 'Exploitation for Privilege Escalation' and T1499, covering 'Network Denial of Service' techniques. The mitigation strategy involves upgrading to Linux kernel version 4.12 or later, where the HNS subsystem properly implements the ETH_SS_PRIV_FLAGS case handling. Additionally, system administrators should implement proper monitoring for unusual network subsystem behavior and consider disabling unnecessary network interfaces when not in use. Organizations should also conduct thorough vulnerability assessments of their network infrastructure to identify systems running vulnerable kernel versions and ensure timely patch deployment to prevent exploitation.
This vulnerability demonstrates the importance of comprehensive testing for edge cases in kernel subsystems and highlights the risks associated with incomplete implementation of standard networking interfaces. The issue serves as a reminder that even seemingly minor omissions in driver implementations can lead to significant security implications, particularly when dealing with network subsystems that handle critical system operations. The combination of local privilege requirements with potential for system-wide impact makes this vulnerability particularly concerning for enterprise environments where network infrastructure stability is paramount.