CVE-2016-4568 in Linux
Summary
by MITRE • 01/25/2023
drivers/media/v4l2-core/videobuf2-v4l2.c in the Linux kernel before 4.5.3 allows local users to cause a denial of service (kernel memory write operation) or possibly have unspecified other impact via a crafted number of planes in a VIDIOC_DQBUF ioctl call.
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Analysis
by VulDB Data Team • 01/25/2023
The vulnerability identified as CVE-2016-4568 resides within the Linux kernel's video4linux2 subsystem, specifically in the videobuf2-v4l2.c driver component. This issue affects Linux kernel versions prior to 4.5.3 and represents a critical security flaw that can be exploited by local attackers to compromise system stability and potentially execute arbitrary code. The vulnerability manifests through improper validation of user-supplied data during video buffer operations, creating a pathway for malicious actors to manipulate kernel memory structures through carefully crafted ioctl system calls.
The technical flaw stems from insufficient bounds checking in the VIDIOC_DQBUF ioctl handler implementation. When a user-space application submits a VIDIOC_DQBUF request with an excessive number of planes, the kernel fails to properly validate this input parameter against predefined limits. This lack of input sanitization allows attackers to specify an abnormally high number of planes that exceeds the allocated memory boundaries for video buffer structures. The vulnerability is classified as a buffer overflow condition that can result in kernel memory corruption, as the system attempts to write data beyond the intended memory allocation regions. This flaw operates at the kernel level, making it particularly dangerous as it can bypass standard user-space protections and directly impact system integrity.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it can potentially enable privilege escalation and arbitrary code execution within the kernel space. Local attackers who can execute code on the target system can leverage this vulnerability to cause system crashes through kernel memory corruption, leading to denial of service conditions that may require system reboot to resolve. In more severe exploitation scenarios, the memory corruption could be manipulated to redirect execution flow or overwrite critical kernel structures, potentially allowing attackers to escalate privileges and gain full control over the affected system. The vulnerability affects systems running Linux kernel versions up to 4.5.2, making it particularly relevant for organizations maintaining older kernel versions in their infrastructure.
Mitigation strategies for CVE-2016-4568 primarily focus on kernel version updates and system hardening measures. The most effective remediation involves upgrading to Linux kernel version 4.5.3 or later, where the vulnerability has been addressed through proper input validation and bounds checking mechanisms. System administrators should also implement kernel lockdown features and disable unnecessary video4linux2 functionality where possible. Additionally, monitoring for unusual VIDIOC_DQBUF ioctl calls and implementing strict access controls for video device interfaces can help detect potential exploitation attempts. This vulnerability aligns with CWE-129, which addresses improper validation of input buffers, and represents a typical example of how inadequate input sanitization in kernel drivers can create severe security implications. Organizations should also consider implementing the ATT&CK framework's privilege escalation techniques to understand potential exploitation paths, as this vulnerability could be leveraged as part of broader attack campaigns targeting kernel-level persistence mechanisms.