CVE-2019-1805 in Wireless LAN Controller
Summary
by MITRE
A vulnerability in certain access control mechanisms for the Secure Shell (SSH) server implementation for Cisco Wireless LAN Controller (WLC) Software could allow an unauthenticated, adjacent attacker to access a CLI instance on an affected device. The vulnerability is due to a lack of proper input- and validation-checking mechanisms for inbound SSH connections on an affected device. An attacker could exploit this vulnerability by attempting to establish an SSH connection to an affected controller. An exploit could allow the attacker to access an affected device's CLI to potentially cause further attacks. This vulnerability has been fixed in version 8.5(140.0).
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Analysis
by VulDB Data Team • 09/04/2023
The vulnerability identified as CVE-2019-1805 represents a critical access control flaw within the Secure Shell implementation of Cisco Wireless LAN Controller software, specifically affecting devices running versions prior to 8.5(140.0). This weakness resides in the authentication and validation mechanisms that govern inbound SSH connections to the wireless controller infrastructure, creating a significant security risk for organizations relying on these network devices for wireless access management. The vulnerability's impact extends beyond simple unauthorized access, as it provides attackers with direct command-line interface access to the affected devices, potentially enabling comprehensive system compromise and further lateral movement within the network infrastructure.
The technical root cause of this vulnerability stems from inadequate input validation and sanitization processes within the SSH server implementation. When an attacker establishes an SSH connection attempt to an affected Cisco WLC device, the system fails to properly validate the connection parameters and authentication requests, allowing unauthorized access to the command-line interface. This flaw operates at the network protocol level where the SSH server should enforce strict authentication boundaries but instead permits connection establishment without proper verification mechanisms. The vulnerability specifically affects adjacent attackers who can directly connect to the device's SSH port, eliminating the need for complex remote exploitation techniques that would typically be required for such attacks.
The operational impact of CVE-2019-1805 extends far beyond simple unauthorized access, as successful exploitation provides attackers with full administrative control over the affected wireless controller. This access enables malicious actors to modify wireless network configurations, disable security features, create unauthorized access points, and potentially establish persistent backdoors within the network infrastructure. The vulnerability's proximity to the core network management functions means that exploitation could result in complete wireless network compromise, affecting thousands of connected devices and potentially providing attackers with a foothold for broader network infiltration. Organizations using affected Cisco WLC versions face significant risk of data breaches, network disruption, and potential compliance violations due to the unauthorized access capabilities this vulnerability enables.
Cisco addressed this vulnerability through software version 8.5(140.0) which implements proper input validation mechanisms for SSH connections and strengthens the authentication processes for inbound connection attempts. The fix involves enhanced validation of SSH connection parameters and improved access control enforcement that prevents unauthorized CLI access attempts. Organizations should prioritize immediate deployment of this security update across all affected Cisco WLC devices to eliminate the risk of exploitation. Additionally, network administrators should implement network segmentation and access controls to limit physical access to wireless controller infrastructure, while monitoring for suspicious SSH connection attempts that might indicate exploitation attempts. This vulnerability aligns with CWE-284, which addresses improper access control in software implementations, and represents a clear violation of the principle of least privilege in network security architecture, as it allows unauthorized access to critical network management functions without proper authentication mechanisms.
The remediation process requires careful planning and execution, as Cisco WLC devices typically serve as critical network infrastructure components that require careful handling during updates. Organizations should conduct thorough testing in controlled environments before deploying the update to production systems to ensure that the security patch does not introduce compatibility issues with existing wireless network configurations. Network administrators should also implement comprehensive monitoring solutions to detect and respond to any exploitation attempts, as the vulnerability's low complexity and high impact make it attractive to both opportunistic and targeted attackers. Regular vulnerability assessments and security audits should be conducted to identify similar access control weaknesses in other network infrastructure components that may present similar risks to the organization's overall security posture.