CVE-2010-4158 in Linux
Summary
by MITRE
The sk_run_filter function in net/core/filter.c in the Linux kernel before 2.6.36.2 does not check whether a certain memory location has been initialized before executing a (1) BPF_S_LD_MEM or (2) BPF_S_LDX_MEM instruction, which allows local users to obtain potentially sensitive information from kernel stack memory via a crafted socket filter.
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Analysis
by VulDB Data Team • 11/23/2024
The vulnerability identified as CVE-2010-4158 resides within the Linux kernel's packet filtering mechanism, specifically in the sk_run_filter function located in net/core/filter.c. This flaw represents a classic information disclosure vulnerability that affects kernel versions prior to 2.6.36.2, where the kernel fails to properly validate memory initialization states before executing certain BPF (Berkeley Packet Filter) instructions. The vulnerability operates through the execution of BPF_S_LD_MEM and BPF_S_LDX_MEM instructions, which are designed to load memory values into BPF registers, but the function does not verify whether the target memory location contains valid data before proceeding with execution.
The technical exploitation of this vulnerability occurs when a local attacker crafts a malicious socket filter that includes these specific BPF instructions, targeting memory locations that may contain uninitialized data from kernel stack memory. When the kernel processes these instructions without proper validation, it inadvertently exposes potentially sensitive information that was previously stored in the uninitialized memory locations. This information could include kernel stack contents, previously used memory values, or other data that should not be accessible to user-space processes. The vulnerability is particularly dangerous because it operates at kernel level, allowing attackers to potentially extract confidential information that could aid in further exploitation attempts or system compromise.
From an operational perspective, this vulnerability enables local privilege escalation attacks that can be particularly devastating in multi-user environments or systems where untrusted users have access to socket filtering capabilities. The impact extends beyond simple information disclosure, as the leaked kernel memory contents could contain sensitive data such as cryptographic keys, session tokens, or other critical system information. Attackers could potentially leverage this information to bypass security mechanisms, perform more sophisticated attacks, or gain deeper insights into the target system's internal state. The vulnerability is classified under CWE-200, which deals with the exposure of sensitive information to an unauthorized actor, and aligns with ATT&CK technique T1005 for data from local system.
Mitigation strategies for CVE-2010-4158 primarily involve updating the Linux kernel to version 2.6.36.2 or later, where the memory validation checks have been implemented. System administrators should also consider implementing additional security measures such as restricting socket filter capabilities for untrusted users, monitoring for suspicious socket filter usage patterns, and ensuring that kernel memory is properly initialized before execution. The vulnerability demonstrates the critical importance of proper input validation and memory management in kernel space, where even seemingly minor oversight can result in significant security implications. Organizations should prioritize patch management and maintain up-to-date kernel versions to protect against similar vulnerabilities that may arise from insufficient validation of memory access operations in kernel-level code.