CVE-2022-48641 in Linux
Summary
by MITRE • 04/28/2024
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ebtables: fix memory leak when blob is malformed
The bug fix was incomplete, it "replaced" crash with a memory leak. The old code had an assignment to "ret" embedded into the conditional, restore this.
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Analysis
by VulDB Data Team • 01/08/2025
The vulnerability CVE-2022-48641 represents a memory leak in the Linux kernel's netfilter ebtables subsystem that emerged from an incomplete bug fix implementation. This issue specifically affects the ebtables framework which is responsible for packet filtering and frame manipulation at the Ethernet bridge level in Linux networking stacks. The problem manifests when processing malformed data blobs within the ebtables subsystem, where the kernel fails to properly release allocated memory resources, leading to gradual memory consumption that can eventually impact system stability and performance.
The technical flaw stems from an erroneous handling of error conditions within the ebtables processing code path. During the initial bug fix attempt, developers replaced a potential system crash with a memory leak scenario, which inadvertently introduced a regression in memory management. The original code structure included an assignment operation to the return value variable "ret" embedded within conditional statements, which was subsequently removed during the fix process. This removal caused the kernel to fail to properly initialize or handle error states, resulting in allocated memory structures not being freed when malformed input data was encountered. The vulnerability operates at the kernel level within the netfilter framework, specifically targeting the ebtables bridge table processing functionality that handles Ethernet frame filtering operations.
The operational impact of this memory leak vulnerability extends beyond simple resource consumption, as it can lead to progressive system degradation and potential denial of service conditions. Attackers could exploit this weakness by crafting malicious network frames or malformed ebtables rules that trigger the memory leak condition repeatedly, causing the system to consume increasing amounts of memory over time. This vulnerability affects systems running Linux kernels with ebtables functionality enabled, particularly those implementing bridge networking configurations where Ethernet frame filtering is utilized. The memory leak may not immediately cause system crashes but can gradually reduce available system resources, potentially affecting network performance and overall system responsiveness. Systems with high network traffic volumes or those running multiple ebtables rules are more susceptible to the cumulative effects of this memory consumption.
Mitigation strategies for CVE-2022-48641 should prioritize applying the official kernel patches released by the Linux kernel security team, which restore the proper error handling mechanism and memory cleanup procedures. Administrators should also implement monitoring solutions to track memory usage patterns and detect unusual consumption trends that might indicate exploitation attempts. Network administrators should review and minimize the use of complex ebtables rules where possible, as simpler rule sets reduce the attack surface. The vulnerability aligns with CWE-401, which addresses improper handling of memory allocation and deallocation, and may be categorized under ATT&CK technique T1070.004 for indicator removal and T1499.004 for network denial of service. Organizations should also consider implementing network segmentation and access controls to limit exposure of systems running ebtables configurations, while maintaining regular kernel updates to address similar memory management vulnerabilities in the netfilter subsystem.