CVE-2017-2712 in S3300
Summary
by MITRE
S3300 V100R006C05 have an Ethernet in the First Mile (EFM) flapping vulnerability due to the lack of type-length-value (TLV) consistency check. An attacker may craft malformed packets and send them to a device to cause EFM flapping.
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Analysis
by VulDB Data Team • 01/11/2023
The CVE-2017-2712 vulnerability affects the S3300 V100R006C05 network equipment, specifically targeting the Ethernet in the First Mile (EFM) functionality. This vulnerability stems from insufficient validation of type-length-value (TLV) structures within the packet processing mechanism, creating a critical security gap that can be exploited by malicious actors. The EFM protocol is designed to provide reliable connectivity in access networks, particularly in scenarios where fiber optic connections terminate at customer premises, making this vulnerability particularly concerning for network infrastructure security.
The technical flaw manifests in the absence of proper TLV consistency checks during packet parsing operations. When malformed packets are crafted and transmitted to affected devices, the system fails to validate the integrity of the TLV structure, leading to unpredictable behavior in the EFM link state management. This lack of validation creates a condition where the device may incorrectly interpret packet contents, resulting in false positive or negative link status notifications. The vulnerability allows an attacker to manipulate the EFM flapping behavior by sending specifically crafted packets that exploit this validation gap, potentially causing legitimate network traffic to be disrupted or dropped due to false link failures.
The operational impact of this vulnerability extends beyond simple network disruption, as EFM flapping can lead to significant service degradation and potential complete network outages. When EFM links flap repeatedly, it causes intermittent connectivity issues that affect customer services, particularly in scenarios where voice and data services depend on stable physical layer connections. The vulnerability enables an attacker to cause sustained disruption by continuously sending malformed packets that trigger link flapping, potentially leading to cascading failures in network services that rely on stable EFM connections. This type of vulnerability can be particularly damaging in enterprise environments where network reliability is critical for business operations.
Mitigation strategies for CVE-2017-2712 should focus on implementing proper TLV validation mechanisms within the packet processing pipeline, ensuring that all incoming packets undergo rigorous consistency checks before being processed by the EFM subsystem. Network administrators should consider applying firmware updates provided by the vendor to address the specific validation gap that allows malformed packets to trigger EFM flapping behavior. Additionally, implementing network segmentation and access control measures can limit the potential impact of such attacks by restricting which systems can send packets to vulnerable EFM interfaces. From a compliance perspective, this vulnerability aligns with CWE-129, which addresses insufficient input validation, and could be classified under ATT&CK technique T1059 for command and control through network protocol manipulation. Organizations should also consider implementing network monitoring solutions that can detect anomalous EFM link state changes and alert administrators to potential exploitation attempts.