CVE-2016-2117 in Linux
Summary
by MITRE
The atl2_probe function in drivers/net/ethernet/atheros/atlx/atl2.c in the Linux kernel through 4.5.2 incorrectly enables scatter/gather I/O, which allows remote attackers to obtain sensitive information from kernel memory by reading packet data.
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Analysis
by VulDB Data Team • 07/27/2022
The vulnerability identified as CVE-2016-2117 represents a critical information disclosure flaw within the Linux kernel's network driver subsystem. This issue affects the atl2_probe function located in drivers/net/ethernet/atheros/atlx/atl2.c, specifically impacting Linux kernel versions through 4.5.2. The flaw stems from an improper configuration of scatter/gather I/O operations during driver initialization, creating a pathway for malicious actors to access sensitive kernel memory contents through crafted network packet analysis.
The technical implementation of this vulnerability involves the incorrect enabling of scatter/gather I/O capabilities within the network driver's probe function. Scatter/gather I/O is a memory management technique that allows data to be transferred in multiple non-contiguous memory segments, which is typically beneficial for performance optimization. However, in this specific case, the driver fails to properly initialize the scatter/gather capabilities, leading to uninitialized memory regions being exposed to network packet processing. When remote attackers send specially crafted packets to a vulnerable system, the malformed scatter/gather operations allow them to read kernel memory contents that should remain protected, potentially exposing sensitive data such as cryptographic keys, passwords, or other confidential information stored in kernel memory spaces.
From an operational perspective, this vulnerability creates significant security implications for systems running affected Linux kernel versions, particularly those operating in networked environments where external traffic is processed. The attack vector requires remote network access and can be executed without authentication, making it particularly dangerous as it can be exploited by any attacker with access to the network. The impact extends beyond simple information disclosure, as the leaked kernel memory could contain critical system information that might aid in subsequent attacks, including privilege escalation or further exploitation of system vulnerabilities. This flaw demonstrates a classic case of improper initialization leading to information leakage, which aligns with CWE-665, improper initialization of a resource, and can be categorized under the ATT&CK technique T1005 for data from local system.
The mitigation strategies for CVE-2016-2117 primarily involve upgrading to a patched Linux kernel version where the scatter/gather I/O initialization has been corrected. System administrators should prioritize applying the relevant kernel updates from their distribution vendors, as the fix typically involves proper initialization of the scatter/gather capabilities within the driver's probe function. Additionally, network segmentation and firewall rules can provide temporary mitigation by limiting access to affected systems, though this approach does not address the root cause. Security monitoring should be enhanced to detect unusual network traffic patterns that might indicate exploitation attempts, while regular security audits should verify that all network-facing systems have been properly patched against this vulnerability. The vulnerability highlights the importance of proper resource initialization in kernel space and serves as a reminder of the critical security implications that can arise from seemingly minor initialization flaws in system components that handle sensitive data processing operations.