CVE-2023-3863 in Linux
Summary
by MITRE • 07/24/2023
A use-after-free flaw was found in nfc_llcp_find_local in net/nfc/llcp_core.c in NFC in the Linux kernel. This flaw allows a local user with special privileges to impact a kernel information leak issue.
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Analysis
by VulDB Data Team • 08/16/2023
The vulnerability identified as CVE-2023-3863 represents a critical use-after-free flaw within the NFC subsystem of the Linux kernel, specifically in the nfc_llcp_find_local function located in net/nfc/llcp_core.c. This type of vulnerability occurs when a program continues to use a pointer after the memory it references has been freed, creating potential for arbitrary code execution or information disclosure. The flaw exists within the NFC logical link control protocol implementation, which handles communication between NFC devices and the kernel's NFC subsystem. The vulnerability's impact is particularly concerning because it affects the kernel's core NFC functionality, which is essential for mobile device NFC operations including contactless payment systems, device pairing, and data exchange protocols.
The technical exploitation of this use-after-free vulnerability requires a local user with special privileges to trigger the flaw, typically through crafted NFC operations or kernel module interactions that cause the nfc_llcp_find_local function to access freed memory. When this occurs, the kernel's memory management system can be manipulated to either leak sensitive information from kernel memory space or potentially execute arbitrary code with kernel privileges. The vulnerability stems from improper memory management within the NFC LLCP (Logical Link Control Protocol) implementation where the function fails to properly validate memory references after object deallocation. This issue is classified under CWE-416 as Use After Free, a well-known vulnerability pattern that has been extensively documented in the cybersecurity community and frequently exploited in kernel-level attacks.
The operational impact of CVE-2023-3863 extends beyond simple information leakage, as it represents a potential path to privilege escalation within the kernel environment. While the vulnerability requires local access with special privileges, in environments where NFC functionality is enabled and accessible to untrusted users, this could provide attackers with a means to gain deeper system access. The attack vector typically involves manipulating NFC communication parameters or device interactions that cause the kernel to process freed memory locations, potentially leading to denial of service conditions or more severe exploitation outcomes. The vulnerability affects various Linux distributions that include NFC support, particularly those with NFC-enabled hardware such as smartphones, tablets, and embedded systems that utilize NFC for secure communication protocols. This flaw aligns with ATT&CK technique T1068 which involves exploiting vulnerabilities in legitimate programs to gain elevated privileges, and T1543 which covers creating or modifying system level processes to maintain persistence.
Mitigation strategies for CVE-2023-3863 should focus on immediate kernel updates from vendors such as Red Hat, Ubuntu, Debian, and other distribution maintainers who have released patches addressing the use-after-free condition. System administrators should prioritize patching affected systems, particularly those running NFC-enabled services or devices where the vulnerability could be exploited through legitimate NFC communication channels. Additional defensive measures include implementing strict access controls for NFC functionality, monitoring for unusual NFC communication patterns, and ensuring that NFC services are not running with unnecessary privileges. The vulnerability highlights the importance of proper memory management in kernel space operations and the need for comprehensive security testing of device drivers and subsystems. Organizations should also consider implementing network segmentation to limit access to NFC-enabled systems and establish monitoring protocols for detecting potential exploitation attempts. Given the nature of the vulnerability and its potential for privilege escalation, continuous vulnerability assessment and patch management programs are essential for maintaining system security posture against similar kernel-level flaws.