CVE-2010-4075 in Linux
Summary
by MITRE
The uart_get_count function in drivers/serial/serial_core.c in the Linux kernel before 2.6.37-rc1 does not properly initialize a certain structure member, which allows local users to obtain potentially sensitive information from kernel stack memory via a TIOCGICOUNT ioctl call.
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Analysis
by VulDB Data Team • 07/01/2024
The vulnerability identified as CVE-2010-4075 represents a classic information disclosure flaw within the Linux kernel's serial communication subsystem. This issue affects versions of the Linux kernel prior to 2.6.37-rc1 and specifically targets the uart_get_count function located in drivers/serial/serial_core.c. The flaw stems from improper initialization of a structure member, creating a potential security risk that could expose sensitive data from kernel memory space. The vulnerability manifests when a local user executes a TIOCGICOUNT ioctl call against a serial port device, which triggers the problematic function and results in information leakage.
The technical implementation of this vulnerability involves the uart_get_count function failing to properly initialize a structure member before returning information to user space. This initialization gap allows kernel stack memory contents to be inadvertently exposed through the ioctl interface. When the TIOCGICOUNT ioctl call is made, the function processes the request but leaves certain memory locations uninitialized, causing previously stored data from kernel memory to persist in the response structure. This type of information disclosure can reveal sensitive kernel data including cryptographic keys, passwords, or other confidential information that may have been previously stored in the affected memory regions.
From an operational perspective, this vulnerability poses a significant risk to systems running affected kernel versions as it enables local privilege escalation attacks. While the vulnerability requires local access to exploit, it can be leveraged by malicious users with limited privileges to gain insights into kernel memory structures. The impact extends beyond simple information disclosure since the leaked data could potentially aid attackers in developing more sophisticated attacks against the system. The vulnerability aligns with CWE-248, which addresses "Uncaught Exception," and represents a form of information exposure that could be exploited in conjunction with other vulnerabilities to compromise system security.
The attack vector for CVE-2010-4075 is limited to local users who have access to the system and can execute the TIOCGICOUNT ioctl call against serial port devices. However, the implications are serious as this vulnerability can be exploited to gather intelligence about the kernel state and memory layout. Security researchers have categorized this issue under ATT&CK technique T1005, which involves OS credential dumping, as the leaked information could potentially aid in credential recovery or system compromise. The vulnerability demonstrates the importance of proper memory initialization in kernel code and highlights the need for comprehensive testing of system interfaces that handle sensitive data.
Mitigation strategies for this vulnerability primarily involve upgrading to Linux kernel version 2.6.37-rc1 or later, where the initialization issue has been resolved. System administrators should prioritize patching affected systems to prevent exploitation. Additional defensive measures include implementing proper access controls to limit local user privileges, monitoring for suspicious ioctl activity, and conducting regular security assessments of kernel interfaces. The vulnerability also underscores the importance of following secure coding practices, particularly in kernel development, where proper initialization of all data structures is critical to preventing information disclosure attacks. Organizations should also consider implementing kernel hardening techniques and maintaining up-to-date security patches to protect against similar vulnerabilities in the future.