CVE-2013-2634 in Linux
Summary
by MITRE
net/dcb/dcbnl.c in the Linux kernel before 3.8.4 does not initialize certain structures, which allows local users to obtain sensitive information from kernel stack memory via a crafted application.
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Analysis
by VulDB Data Team • 01/01/2022
The vulnerability identified as CVE-2013-2634 resides within the Linux kernel's Data Center Bridging Netlink (DCB) subsystem, specifically in the net/dcb/dcbnl.c file. This flaw represents a classic case of improper initialization that can lead to information disclosure, making it particularly concerning for systems where kernel memory exposure could be exploited by malicious local users. The vulnerability affects Linux kernel versions prior to 3.8.4, indicating it was present in a significant portion of kernel releases during that timeframe.
The technical root cause of this vulnerability stems from the failure to properly initialize certain data structures within the DCB netlink interface implementation. When applications interact with the DCB subsystem through netlink sockets, the kernel processes these requests and populates response structures. However, due to missing initialization calls, portions of these structures retain data from previous operations or contain uninitialized memory contents that were previously allocated within kernel stack memory. This uninitialized memory may contain sensitive information such as cryptographic keys, credentials, or other confidential data that was previously stored in the same memory locations.
The operational impact of this vulnerability is significant for local attackers who can craft malicious applications to exploit this information disclosure flaw. Since the vulnerability requires local execution privileges, it primarily affects scenarios where untrusted users have access to the system or where privilege escalation is already possible through other means. Attackers can leverage this weakness to extract potentially sensitive information from kernel memory, which could include system configuration details, network state information, or other data that might aid in further exploitation attempts. The vulnerability aligns with CWE-1289, which specifically addresses the improper initialization of structures and variables, and represents a common pattern in kernel security flaws that can be exploited for information gathering.
From an attack perspective, this vulnerability fits within the ATT&CK framework under the technique of "T1005 - Data from Local System" and potentially "T1059 - Command and Scripting Interpreter" as attackers might use the leaked information to craft more sophisticated attacks. The information disclosure occurs through the DCB netlink interface, which is typically used for managing Data Center Bridging features in network switches and routers. The fact that this vulnerability exists in kernel space makes it particularly dangerous as it can provide access to memory that contains privileged information not normally accessible to user-space applications.
The recommended mitigations for this vulnerability include applying the kernel patch released with version 3.8.4, which properly initializes the affected structures to prevent information leakage from kernel memory. System administrators should prioritize updating their kernel versions to ensure protection against this and similar information disclosure vulnerabilities. Additionally, organizations should implement monitoring for suspicious network traffic patterns that might indicate exploitation attempts, particularly around DCB-related netlink operations. The vulnerability also highlights the importance of thorough code review processes that specifically examine kernel code for proper initialization of all data structures, especially those used in system call interfaces where uninitialized memory can be exposed to user-space applications. This case demonstrates the critical need for defensive programming practices in kernel development, where every data structure must be properly initialized to prevent information leakage that could compromise system security.