CVE-2002-2371 in WET11
Summary
by MITRE
Linksys WET11 firmware 1.31 and 1.32 allows remote attackers to cause a denial of service (crash) via a packet containing the device s hardware address as the source MAC address in the DLC header.
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Analysis
by VulDB Data Team • 07/14/2024
The vulnerability described in CVE-2002-2371 affects Linksys WET11 wireless Ethernet bridge devices running firmware versions 1.31 and 1.32. This represents a classic denial of service flaw that exploits the device's handling of data link layer packets. The vulnerability specifically targets the Data Link Control (DLC) header processing within the network stack of these wireless bridges, which are commonly deployed in enterprise and small business environments to extend wired network coverage through wireless connections.
The technical flaw occurs when the wireless bridge receives a malformed packet where the source MAC address in the DLC header matches the device's own hardware address. This condition creates a scenario where the device's network processing routines become confused during packet validation and forwarding operations. The device fails to properly validate incoming packets against its own hardware address, leading to an unpredictable state that ultimately results in the device crashing and becoming unavailable to legitimate network users. This type of vulnerability falls under CWE-129, which describes improper validation of input data, and specifically relates to improper handling of network protocol elements within the data link layer.
The operational impact of this vulnerability is significant for organizations relying on these wireless bridges for network connectivity. A remote attacker can exploit this flaw from outside the network perimeter to disrupt critical network services, potentially affecting business operations and causing productivity losses. The vulnerability is particularly dangerous because it requires no authentication or specialized access privileges, making it an attractive target for malicious actors seeking to cause disruption. The device's crash results in complete network service interruption for the wireless segment it serves, potentially affecting multiple users and applications dependent on that network connection. This vulnerability aligns with ATT&CK technique T1498, which describes denial of service attacks that target network infrastructure components.
Mitigation strategies for this vulnerability should include immediate firmware updates from Linksys to address the specific packet handling flaw. Network administrators should also implement network segmentation and access controls to limit exposure of these devices to untrusted networks. Additional protective measures include monitoring network traffic for suspicious patterns that might indicate exploitation attempts and implementing network intrusion detection systems that can identify malformed DLC header packets. Organizations should also consider deploying redundant network infrastructure to minimize the impact of potential exploitation attempts, as the vulnerability effectively renders the device unusable until manual intervention or power cycling occurs. The vulnerability demonstrates the importance of proper input validation at all network protocol layers and highlights the critical need for regular firmware updates in network infrastructure devices.