CVE-2018-15556 in Actiontec WEB6000Q
Summary
by MITRE
The Quantenna WiFi Controller on Telus Actiontec WEB6000Q v1.1.02.22 allows login with root level access with the user "root" and an empty password by using the enabled onboard UART headers.
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Analysis
by VulDB Data Team • 10/08/2023
The vulnerability identified as CVE-2018-15556 represents a critical authentication flaw in the Quantenna WiFi Controller firmware running on Telus Actiontec WEB6000Q version 1.1.02.22. This issue stems from improper credential handling that allows unauthorized administrative access through a well-known and documented method. The flaw specifically manifests when an attacker gains physical access to the device through its onboard UART headers, which are typically used for debugging and development purposes but remain accessible in production environments. The vulnerability is classified under CWE-259 as a weakness related to the use of hard-coded credentials, while also aligning with CWE-312 for exposure of sensitive information through improper handling of authentication mechanisms. The presence of default credentials combined with accessible physical interfaces creates a significant security risk that directly violates security best practices established in industry standards and frameworks.
The technical exploitation of this vulnerability occurs through the physical access point provided by the UART headers, which are commonly found on networking equipment for diagnostic purposes. When an attacker connects to these headers, they can directly access the device's console interface and authenticate using the hardcoded credentials of "root" with an empty password. This method bypasses all network-based authentication controls and security measures, effectively providing complete administrative control over the device. The vulnerability is particularly concerning because UART interfaces are often left enabled in production devices for troubleshooting purposes, creating an attack surface that is both accessible and persistent. This type of flaw demonstrates a fundamental failure in secure device design and configuration management, as the device should not provide administrative access through such simple means without proper physical security controls.
The operational impact of this vulnerability extends far beyond the immediate device compromise, as it allows attackers to gain complete control over the wireless network infrastructure. Once authenticated, an attacker can modify network configurations, implement man-in-the-middle attacks, monitor network traffic, and potentially use the compromised device as a pivot point for accessing other systems within the network. The attack vector is particularly dangerous because it requires minimal technical expertise and can be executed by an attacker with physical access to the device, which is often achievable in enterprise or residential environments where such equipment is deployed. This vulnerability directly maps to several tactics in the MITRE ATT&CK framework under the Initial Access and Privilege Escalation domains, specifically targeting the use of physical access and credential access techniques. The risk is compounded by the fact that the device is likely part of a larger network infrastructure, potentially providing attackers with access to sensitive internal systems and data.
Mitigation strategies for this vulnerability must address both the immediate security gap and the underlying design flaws that enabled the issue. Organizations should immediately disable or physically secure the UART headers on all affected devices, ensuring that these interfaces are not accessible to unauthorized individuals. The firmware should be updated to remove hardcoded credentials and implement proper authentication mechanisms, including the use of strong, randomly generated passwords for administrative accounts. Network segmentation and monitoring should be implemented to detect unauthorized access attempts and anomalous behavior patterns that may indicate exploitation. Additionally, device hardening procedures should be established to ensure that physical security controls are maintained and that default configurations are properly secured. The remediation process should include comprehensive testing to verify that the UART interfaces are properly disabled and that alternative access methods are properly secured. Organizations should also implement regular security assessments and vulnerability scanning procedures to identify similar issues in other network equipment and ensure that physical security controls are maintained across all network infrastructure components.