CVE-2010-4650 in Linux
Summary
by MITRE
Buffer overflow in the fuse_do_ioctl function in fs/fuse/file.c in the Linux kernel before 2.6.37 allows local users to cause a denial of service or possibly have unspecified other impact by leveraging the ability to operate a CUSE server.
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Analysis
by VulDB Data Team • 12/05/2021
The vulnerability identified as CVE-2010-4650 represents a critical buffer overflow flaw within the Linux kernel's FUSE (Filesystem in Userspace) subsystem. This issue resides in the fuse_do_ioctl function located in fs/fuse/file.c and affects Linux kernel versions prior to 2.6.37. The vulnerability arises from insufficient input validation and bounds checking when processing ioctl commands from CUSE (Character device in Userspace) servers, creating a potential attack vector for local malicious actors.
The technical implementation of this flaw occurs when a local user operates a CUSE server that can trigger the buffer overflow condition within the kernel space. The fuse_do_ioctl function fails to properly validate the size of data structures being passed through ioctl calls, allowing an attacker to write beyond the allocated buffer boundaries. This condition manifests when the kernel processes specific ioctl operations that are part of the FUSE protocol implementation, particularly those involving character device operations that utilize the CUSE framework. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, where the overflow occurs in kernel memory space rather than user space, amplifying the potential impact.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable more severe security consequences. While the primary effect is a system crash or denial of service that can disrupt normal system operations, the local nature of the exploit means that an attacker with limited privileges can leverage this vulnerability to cause system instability. The attack requires local access and the ability to operate a CUSE server, making it accessible to users who have already gained some level of system access. However, the kernel-level execution context of the overflow means that even a local user can potentially escalate their privileges or cause system-wide disruptions that could affect other running processes and services. This vulnerability aligns with ATT&CK technique T1068 which covers the exploitation of local privilege escalation opportunities.
Mitigation strategies for CVE-2010-4650 primarily focus on kernel version updates and system hardening measures. The most effective solution involves upgrading to Linux kernel version 2.6.37 or later, where the buffer overflow has been patched through proper bounds checking and input validation. System administrators should also implement strict access controls for CUSE server operations and monitor for unauthorized FUSE or CUSE module usage. Additional protective measures include disabling unnecessary FUSE functionality when not required, implementing proper user privilege separation, and maintaining comprehensive system monitoring to detect unusual ioctl activity patterns. The vulnerability demonstrates the importance of kernel security auditing and proper input validation in kernel space operations, particularly for subsystems that interface with user-space processes through complex communication protocols. Organizations should also consider implementing automated patch management systems to ensure timely deployment of kernel security updates and maintain detailed system inventories to track FUSE module usage across their environments.