CVE-2013-3233 in Linux
Summary
by MITRE
The llcp_sock_recvmsg function in net/nfc/llcp/sock.c in the Linux kernel before 3.9-rc7 does not initialize a certain length variable and a certain data structure, which allows local users to obtain sensitive information from kernel stack memory via a crafted recvmsg or recvfrom system call.
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Analysis
by VulDB Data Team • 05/10/2021
The vulnerability identified as CVE-2013-3233 represents a critical information disclosure flaw within the Linux kernel's NFC (Near Field Communication) subsystem, specifically affecting versions prior to 3.9-rc7. This issue resides in the llcp_sock_recvmsg function located in net/nfc/llcp/sock.c, where insufficient initialization of critical kernel data structures creates a pathway for unauthorized information leakage. The vulnerability manifests when local users execute crafted recvmsg or recvfrom system calls against NFC communication endpoints, enabling them to access sensitive data that should remain protected within kernel memory spaces.
The technical root cause of this vulnerability stems from improper initialization of a length variable and associated data structure within the NFC link layer communication protocol implementation. According to CWE-457, this represents a use of uninitialized variable vulnerability where the kernel function fails to properly establish initial values before utilizing memory locations. The uninitialized variables contain residual data from previous operations that may include sensitive kernel memory contents, including cryptographic keys, session tokens, or other confidential information. When the recvmsg or recvfrom system calls are invoked, this uninitialized memory gets returned to user-space applications, effectively leaking kernel stack contents to potentially malicious local processes.
The operational impact of CVE-2013-3233 extends beyond simple information disclosure, as it provides attackers with access to kernel memory that could contain highly sensitive data. This vulnerability operates under the ATT&CK framework's technique T1005 - Data from Local System, where adversaries can extract information from compromised systems. The local privilege escalation aspect becomes particularly concerning since an attacker with user-level access can potentially obtain kernel memory contents that may reveal system configuration details, memory layout information, or other sensitive data that could be leveraged for further exploitation. The vulnerability affects systems running Linux kernel versions where NFC functionality is enabled and accessible, particularly those supporting NFC hardware interfaces such as smartphones, tablets, and other devices with NFC capabilities.
Mitigation strategies for CVE-2013-3233 primarily involve upgrading to Linux kernel version 3.9-rc7 or later, which includes the necessary patches to properly initialize the affected variables and data structures. System administrators should also implement least privilege principles to limit local user access to NFC subsystems where possible, though this does not address the core vulnerability. Additionally, monitoring for suspicious recvmsg or recvfrom system calls against NFC interfaces can help detect potential exploitation attempts. The patch implemented by the Linux kernel team specifically addresses the uninitialized variable issue by ensuring proper initialization of the length parameter and associated data structures before they are utilized in the NFC communication handling code. Organizations should prioritize patch management processes to ensure all systems running affected kernel versions receive the necessary security updates to prevent exploitation of this information disclosure vulnerability.