CVE-2016-5829 in Linux
Summary
by MITRE • 01/25/2023
Multiple heap-based buffer overflows in the hiddev_ioctl_usage function in drivers/hid/usbhid/hiddev.c in the Linux kernel through 4.6.3 allow local users to cause a denial of service or possibly have unspecified other impact via a crafted (1) HIDIOCGUSAGES or (2) HIDIOCSUSAGES ioctl call.
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Analysis
by VulDB Data Team • 01/25/2023
The vulnerability identified as CVE-2016-5829 represents a critical heap-based buffer overflow condition within the Linux kernel's USB HID device handling subsystem. This flaw exists in the hiddev_ioctl_usage function located in drivers/hid/usbhid/hiddev.c and affects kernel versions through 4.6.3, making it a persistent threat across multiple kernel releases. The vulnerability stems from inadequate input validation and bounds checking when processing HIDIOCGUSAGES and HIDIOCSUSAGES ioctl commands, which are used to communicate with Human Interface Device interfaces such as keyboards, mice, and other input peripherals. These ioctl calls are essential for device configuration and data retrieval operations within the Linux HID subsystem, creating a significant attack surface for malicious actors who can exploit the vulnerability through crafted ioctl requests.
The technical implementation of this vulnerability involves the kernel's failure to properly validate the size parameters associated with HID usage arrays when processing ioctl commands. When a local user executes a crafted HIDIOCGUSAGES or HIDIOCSUSAGES ioctl call, the kernel allocates memory on the heap based on potentially untrusted input values without sufficient boundary checks. This allows attackers to write beyond the allocated buffer boundaries, corrupting adjacent heap memory structures and potentially leading to memory corruption that can be exploited for privilege escalation or system instability. The heap overflow occurs because the kernel does not validate that the requested usage array size does not exceed the allocated buffer capacity, enabling attackers to overwrite critical heap metadata or adjacent memory regions that contain important kernel data structures.
From an operational perspective, this vulnerability presents a significant risk to Linux systems as it allows local users to cause either denial of service conditions or potentially achieve more severe impacts including privilege escalation. The denial of service aspect manifests through system crashes, kernel oops messages, and complete system lockups when the heap corruption leads to memory management subsystem failures. However, the more concerning aspect is the potential for unspecified other impacts that could include privilege escalation to kernel mode, allowing attackers to execute arbitrary code with the highest system privileges. The vulnerability's local nature means that exploitation requires only user-level access to the system, making it particularly dangerous as it can be leveraged by malware or compromised accounts to gain root access. This aligns with ATT&CK technique T1068 which covers 'Local Privilege Escalation' and CWE-121 which addresses 'Stack-based Buffer Overflow' and its heap-based variants.
The mitigation strategies for CVE-2016-5829 primarily involve applying the official kernel patches released by the Linux kernel security team, which include proper input validation and bounds checking mechanisms for the affected ioctl commands. System administrators should prioritize updating to kernel versions 4.7 or later where this vulnerability has been addressed through enhanced parameter validation and memory allocation safeguards. Additionally, implementing proper access controls and limiting user privileges on systems where HID devices are present can reduce the attack surface, though this does not eliminate the vulnerability entirely. The fix typically involves adding comprehensive bounds checking before memory allocation occurs and ensuring that all ioctl parameter values are validated against expected ranges. Organizations should also consider monitoring for unusual ioctl activity patterns that might indicate exploitation attempts, particularly around HID device operations, as part of their overall security monitoring strategy. This vulnerability demonstrates the critical importance of input validation in kernel space operations and highlights the need for robust memory safety mechanisms in operating system components that handle external device communications.