CVE-2009-3228 in Linux
Summary
by MITRE
The tc_fill_tclass function in net/sched/sch_api.c in the tc subsystem in the Linux kernel 2.4.x before 2.4.37.6 and 2.6.x before 2.6.31-rc9 does not initialize certain (1) tcm__pad1 and (2) tcm__pad2 structure members, which might allow local users to obtain sensitive information from kernel memory via unspecified vectors.
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Analysis
by VulDB Data Team • 12/07/2024
The vulnerability identified as CVE-2009-3228 resides within the Linux kernel's traffic control subsystem, specifically in the tc_fill_tclass function located in net/sched/sch_api.c. This flaw affects kernel versions 2.4.x prior to 2.4.37.6 and 2.6.x prior to 2.6.31-rc9, representing a significant security concern that could potentially expose sensitive kernel memory contents to local attackers. The vulnerability stems from improper initialization of critical structure members within the traffic control API implementation, creating a potential information disclosure channel that adversaries could exploit for privilege escalation or further attack vectors.
The technical root cause of this vulnerability lies in the insufficient initialization of the tcm__pad1 and tcm__pad2 members within the tc_fill_tclass function. These padding fields, which are part of the traffic control message structure, are not properly zeroed or initialized before being populated with data. When the function processes traffic control class information, it fails to clear these memory regions, leaving behind residual data from previous operations or kernel memory allocations. This incomplete initialization creates a scenario where sensitive information from kernel memory space could be inadvertently exposed through the traffic control interface, potentially revealing kernel addresses, configuration details, or other confidential data that should remain protected within kernel memory.
The operational impact of CVE-2009-3228 extends beyond simple information disclosure, as local attackers could leverage this vulnerability to gather intelligence about the kernel's memory layout and operational state. This reconnaissance capability could serve as a foundation for more sophisticated attacks, including kernel exploitation attempts or privilege escalation maneuvers. The vulnerability affects any local user who can interact with the traffic control subsystem through the tc command or related interfaces, making it particularly concerning in multi-user environments where untrusted users might have access to network configuration utilities. The exposure of kernel memory contents could potentially reveal information about kernel version, memory layout, or even sensitive data structures that could aid in bypassing security mechanisms.
This vulnerability aligns with CWE-1283, which addresses improper initialization of structure members, and represents a classic example of information exposure through uninitialized memory. From an adversarial perspective, the flaw maps to ATT&CK technique T1068, which involves privilege escalation through local exploitation, and T1005, covering data from local system. The attack vector is particularly relevant in environments where local users have access to traffic control commands, as they could potentially abuse this information disclosure to gain deeper insights into the kernel's operational state and memory organization. The vulnerability demonstrates the critical importance of proper memory initialization in kernel space, where even seemingly benign initialization oversights can create significant security implications. Organizations should prioritize patching affected kernel versions to mitigate this risk, as the information disclosure could serve as a stepping stone for more advanced attacks targeting kernel memory management or privilege escalation mechanisms.