CVE-2016-6162 in Linux
Summary
by MITRE
net/core/skbuff.c in the Linux kernel 4.7-rc6 allows local users to cause a denial of service (panic) or possibly have unspecified other impact via certain IPv6 socket operations.
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Analysis
by VulDB Data Team • 03/22/2019
The vulnerability identified as CVE-2016-6162 resides within the Linux kernel's networking subsystem, specifically in the net/core/skbuff.c file. This flaw manifests as a local privilege escalation vulnerability that can be exploited by unprivileged users to trigger a kernel panic or potentially achieve more severe consequences. The vulnerability is particularly concerning because it operates within the core networking infrastructure of the Linux operating system, making it accessible through normal user-space operations that involve IPv6 socket handling. The affected kernel version 4.7-rc6 represents a release candidate that was in the testing phase, indicating that this vulnerability was present in the development cycle and had not yet been patched in stable releases.
The technical nature of this vulnerability stems from improper handling of IPv6 socket operations within the kernel's socket buffer management system. When local users perform certain IPv6 socket operations, the kernel's skbuff.c component fails to properly validate or handle specific data structures, leading to memory corruption or invalid memory access patterns. This flaw falls under the category of improper input validation and memory management issues that are commonly classified as CWE-121 and CWE-125 within the CWE database. The vulnerability is particularly insidious because it requires no special privileges to exploit, as it operates from within the user-space context and leverages legitimate kernel functionality to cause system instability.
The operational impact of CVE-2016-6162 extends beyond simple denial of service conditions, as the potential for unspecified other impacts suggests that exploitation might lead to more serious consequences including system crashes, data corruption, or even privilege escalation to root level access. The fact that this vulnerability can cause kernel panics indicates that the underlying memory corruption is severe enough to trigger the kernel's panic mechanism, which is designed to halt system operation when critical errors are detected. From an attack perspective, this vulnerability aligns with techniques described in the MITRE ATT&CK framework under the T1068 category for 'Exploitation for Privilege Escalation' and T1499 for 'Endpoint Denial of Service' as it can be used to disrupt system availability and potentially gain elevated privileges. The local nature of the exploit means that attackers do not require network access or remote system compromise, making this vulnerability particularly dangerous in environments where local access is possible.
Mitigation strategies for CVE-2016-6162 primarily involve applying the appropriate kernel security patches that address the memory handling issues in the socket buffer management code. System administrators should immediately update to kernel versions that contain the fix for this vulnerability, which was included in subsequent stable releases following the 4.7-rc6 version. Additionally, implementing network segmentation and access controls to limit local user access can provide defense-in-depth measures. The vulnerability demonstrates the importance of thorough testing of kernel components, particularly those handling network protocols, and highlights the need for proper input validation and memory management practices in kernel space code. Organizations should also consider monitoring for unusual system behavior or kernel panic events that might indicate exploitation attempts, as these events can serve as early warning indicators of potential security incidents.