CVE-2015-4001 in Linux
Summary
by MITRE
Integer signedness error in the oz_hcd_get_desc_cnf function in drivers/staging/ozwpan/ozhcd.c in the OZWPAN driver in the Linux kernel through 4.0.5 allows remote attackers to cause a denial of service (system crash) or possibly execute arbitrary code via a crafted packet.
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Analysis
by VulDB Data Team • 05/20/2022
The vulnerability identified as CVE-2015-4001 represents a critical integer signedness error within the OZWPAN driver component of the Linux kernel version 4.0.5 and earlier. This flaw exists in the oz_hcd_get_desc_cnf function located in drivers/staging/ozwpan/ozhcd.c, which handles communication with wireless peripheral devices through the OZWPAN subsystem. The vulnerability stems from improper handling of signed integer values during packet processing, creating a scenario where maliciously crafted packets can trigger unexpected behavior in the kernel's memory management and execution flow.
The technical implementation of this vulnerability involves a classic signedness error where the kernel function fails to properly validate or convert signed integer values when processing device descriptor confirmation packets. When remote attackers send specially crafted packets containing malformed signed integer values, the function processes these inputs without adequate bounds checking or type conversion, leading to unpredictable memory access patterns. This error condition can result in kernel memory corruption, where the signed integer overflow or underflow causes invalid memory pointers to be dereferenced, ultimately leading to system crashes or potentially allowing privilege escalation.
From an operational perspective, this vulnerability presents significant risk to systems utilizing the OZWPAN driver, particularly those in wireless networking environments where remote packet injection is possible. The impact extends beyond simple denial of service to potentially enable arbitrary code execution, making it a severe security concern for embedded systems, IoT devices, and wireless infrastructure components that rely on the Linux kernel's wireless subsystem. The vulnerability's exploitation requires remote packet delivery, making it accessible to attackers in networked environments without physical access to the target systems.
The flaw aligns with CWE-191, which specifically addresses integer underflow and the subsequent potential for memory corruption, and demonstrates characteristics consistent with ATT&CK technique T1068, which involves exploiting legitimate credentials and system access to gain elevated privileges. Organizations utilizing Linux systems with wireless capabilities should prioritize patching this vulnerability, as the kernel version 4.0.5 and earlier contain this flaw. The recommended mitigation involves upgrading to kernel versions 4.1 and later, where the integer signedness error has been corrected through proper input validation and type conversion mechanisms. Additionally, network segmentation and packet filtering should be implemented to limit exposure to potential attackers, while continuous monitoring of system logs for unusual memory access patterns can help detect exploitation attempts.