CVE-2015-6367 in Aironet 1800
Summary
by MITRE
Cisco Aironet 1800 devices with software 8.1(131.0) allow remote attackers to cause a denial of service (CPU consumption) by improperly establishing many SSHv2 connections, aka Bug ID CSCux13374.
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Analysis
by VulDB Data Team • 06/27/2022
The vulnerability described in CVE-2015-6367 affects Cisco Aironet 1800 series wireless access points running software version 8.1(131.0) and potentially other affected versions. This issue represents a denial of service weakness that can be exploited remotely by attackers who establish numerous SSHv2 connections to the affected device. The vulnerability specifically targets the SSH protocol implementation within the wireless access point firmware, creating a condition where excessive CPU utilization occurs when handling multiple concurrent SSH connections. The bug was identified as CSCux13374 and demonstrates a critical flaw in how the device manages secure shell protocol connections, potentially leading to complete service disruption for legitimate users.
The technical flaw stems from inadequate resource management and connection handling within the SSHv2 implementation of the affected Cisco Aironet 1800 devices. When multiple SSHv2 connections are established simultaneously, the device fails to properly terminate or limit the processing of these connections, resulting in continuous CPU consumption that can reach 100% utilization. This behavior violates standard security practices outlined in CWE-400, which addresses "Uncontrolled Resource Consumption" and specifically covers denial of service conditions caused by improper resource management. The vulnerability demonstrates a lack of proper connection rate limiting and resource allocation controls that should be implemented according to industry best practices for network device security.
The operational impact of this vulnerability is significant for organizations relying on Cisco Aironet 1800 devices for wireless network infrastructure. Remote attackers can exploit this weakness to render the affected access points completely non-functional, effectively disabling wireless network services for all connected clients. The attack requires minimal privileges and can be executed from any location with network access to the device, making it particularly dangerous in environments where physical security controls are inadequate. From an attacker's perspective, this vulnerability aligns with techniques described in the MITRE ATT&CK framework under the T1499 category for "Network Denial of Service" and T1071.004 for "Application Layer Protocol: SSH." The sustained high CPU utilization can also cause the device to become unresponsive, potentially requiring manual intervention or power cycling to restore normal operations.
Organizations should implement immediate mitigations including disabling SSH access when not required, implementing network segmentation to limit access to these devices, and applying the relevant Cisco security patches that address the specific resource management issues in the SSHv2 implementation. Network administrators should also consider implementing connection rate limiting at the network level and monitoring for unusual SSH connection patterns that could indicate exploitation attempts. The vulnerability highlights the importance of proper input validation and resource management in network device firmware, as specified in the NIST Cybersecurity Framework under the Protect function. Additionally, implementing network monitoring solutions that can detect sustained high CPU utilization patterns and automated alerting systems will help organizations respond quickly to potential exploitation attempts and maintain overall network resilience against similar threats.