CVE-2009-1186 in udev
Summary
by MITRE
Buffer overflow in the util_path_encode function in udev/lib/libudev-util.c in udev before 1.4.1 allows local users to cause a denial of service (service outage) via vectors that trigger a call with crafted arguments.
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Analysis
by VulDB Data Team • 09/01/2019
The vulnerability identified as CVE-2009-1186 represents a critical buffer overflow flaw within the udev device management system that affects versions prior to 1.4.1. This issue resides in the util_path_encode function located in udev/lib/libudev-util.c, which is a core component responsible for handling device path encoding operations within the udev framework. The udev system serves as the device manager for Linux systems, dynamically creating and removing device nodes in the /dev directory while managing device events and associations. When crafted arguments are passed to this vulnerable function, the buffer overflow condition occurs, potentially leading to system instability and service disruption.
The technical nature of this vulnerability stems from inadequate input validation and bounds checking within the util_path_encode function. Buffer overflow conditions typically occur when more data is written to a fixed-length buffer than it can accommodate, causing adjacent memory locations to be overwritten. In this case, local users can exploit the lack of proper argument validation to supply malicious input that exceeds the allocated buffer space, resulting in memory corruption that can cause the udev daemon to crash or behave unpredictably. The vulnerability specifically targets the device management subsystem, which is fundamental to Linux system operation, making it particularly dangerous as it can disrupt the entire device handling mechanism.
The operational impact of this vulnerability extends beyond simple denial of service, as it can compromise the stability and reliability of Linux systems that rely on udev for proper device management. When the udev daemon crashes due to this buffer overflow, the system may experience failures in device node creation, removal, or management, potentially leading to complete system instability. Attackers can leverage this vulnerability to repeatedly crash the udev service, creating persistent denial of service conditions that can render the system unusable for device-related operations. The local privilege requirement means that any user with access to the system can potentially exploit this vulnerability, making it particularly concerning for multi-user environments where privilege escalation is not required.
This vulnerability aligns with CWE-121, which categorizes buffer overflow conditions as a fundamental weakness in software design, and relates to the broader category of memory safety issues that have been extensively documented in security literature. The ATT&CK framework would classify this vulnerability under T1499.004, which covers "Endpoint Denial of Service," as it enables local users to cause service outages through exploitation of system components. The remediation strategy involves upgrading to udev version 1.4.1 or later, where proper input validation and buffer bounds checking have been implemented to prevent the overflow condition. Additionally, system administrators should consider implementing proper access controls and monitoring for unusual udev daemon behavior to detect potential exploitation attempts. The vulnerability demonstrates the critical importance of input validation in system-level software components and highlights how flaws in device management systems can have cascading effects on overall system stability and security posture.