CVE-2016-5870 in Linux
Summary
by MITRE
The msm_ipc_router_close function in net/ipc_router/ipc_router_socket.c in the ipc_router component for the Linux kernel 3.x, as used in Qualcomm Innovation Center (QuIC) Android contributions for MSM devices and other products, allow attackers to cause a denial of service (NULL pointer dereference) or possibly have unspecified other impact by triggering failure of an accept system call for an AF_MSM_IPC socket.
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Analysis
by VulDB Data Team • 11/27/2022
The vulnerability identified as CVE-2016-5870 resides within the msm_ipc_router_close function of the Linux kernel's ipc_router component, specifically in the net/ipc_router/ipc_router_socket.c file. This flaw affects Linux kernel versions 3.x and is particularly prevalent in Qualcomm Innovation Center (QuIC) Android contributions for MSM devices and related products. The vulnerability manifests when an attacker triggers a failure in the accept system call for AF_MSM_IPC sockets, creating a scenario where the kernel experiences a NULL pointer dereference condition. This represents a critical security flaw that can be exploited to disrupt normal system operations and potentially enable more sophisticated attacks.
The technical implementation of this vulnerability stems from improper handling of socket closure operations within the MSM IPC (Inter-Process Communication) router subsystem. When the accept system call fails for AF_MSM_IPC sockets, the msm_ipc_router_close function attempts to process the closure event without adequate validation of pointer states. This leads to a NULL pointer dereference condition where the kernel tries to access memory locations that have not been properly initialized or allocated. The flaw directly maps to CWE-476 which identifies NULL pointer dereference as a common weakness in software security, where a program attempts to access a memory location through a pointer that has not been properly initialized to point to valid memory.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable more severe security consequences. A successful exploitation can result in system crashes, complete service disruption, and in some scenarios may provide attackers with opportunities to escalate privileges or execute arbitrary code within the kernel space. The affected MSM devices represent a significant portion of Android smartphones and tablets that rely on Qualcomm's proprietary IPC mechanisms for communication between different system components and applications. This vulnerability affects the fundamental communication infrastructure of these devices, potentially compromising the integrity and availability of critical system functions.
From an attacker's perspective, this vulnerability represents a low-complexity exploit that can be leveraged to cause system instability and denial of service conditions. The attack vector requires only triggering a failure in the accept system call for AF_MSM_IPC sockets, which can be accomplished through various means including malformed socket operations or network-based attacks. The exploitation aligns with ATT&CK technique T1499.004 which covers network denial of service attacks, and potentially T1068 which addresses local privilege escalation through kernel vulnerabilities. Organizations and device manufacturers must prioritize patching this vulnerability as it represents a significant risk to device stability and security.
Mitigation strategies for CVE-2016-5870 primarily involve applying the appropriate kernel security patches provided by Qualcomm and the Linux kernel maintainers. System administrators should ensure that all affected MSM-based devices receive timely updates to address this vulnerability. Additionally, network monitoring systems should be configured to detect unusual socket closure patterns that might indicate exploitation attempts. The vulnerability highlights the importance of proper input validation and pointer management in kernel space code, emphasizing the need for comprehensive security testing of IPC mechanisms and system call handlers. Device manufacturers should implement stricter validation procedures for socket operations and ensure that all kernel components properly handle error conditions without relying on uninitialized pointers.