CVE-2019-3422 in MF910S
Summary
by MITRE
Security researcher Shen Ying from the Sec Consult Security Lab reported an information disclosure vulnerability in MF910S product to ZTE PSIRT in October 2019. Through the analysis of related product team, the information disclosure vulnerability is confirmed. The MF910S product's one-click upgrade tool can obtain the Telnet remote login password in the reverse way. If Telnet is opened, the attacker can remotely log in to the device through the cracked password, resulting in information leakage. The MF910S was end of service on October 23, 2019, ZTE recommends users to choose new products for the purpose of better security.
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Analysis
by VulDB Data Team • 02/05/2024
The vulnerability identified as CVE-2019-3422 represents a critical information disclosure flaw in ZTE's MF910S device, demonstrating how legacy systems can harbor significant security risks even after their official service lifecycle has ended. This vulnerability specifically affects the one-click upgrade tool functionality within the MF910S product line, where the system's design allows for reverse engineering of Telnet authentication credentials through the upgrade process. The security researcher who discovered this weakness, Shen Ying from Sec Consult Security Lab, reported the issue directly to ZTE's Product Security Incident Response Team in October 2019, following standard vulnerability disclosure protocols that align with industry best practices for responsible disclosure. The confirmed nature of this vulnerability indicates that ZTE's internal product analysis team validated the reported weakness, confirming that the upgrade tool's implementation contains a design flaw that exposes sensitive authentication information.
The technical implementation of this vulnerability stems from improper handling of authentication credentials within the device's upgrade mechanism, where the reverse engineering process enables attackers to extract the Telnet password without requiring legitimate access or authentication. This flaw directly violates security principles that mandate proper credential management and authentication separation, representing a violation of CWE-200 (Information Exposure) and potentially CWE-312 (Sensitive Data Exposure) categories. When Telnet services remain enabled on the device, attackers can leverage this extracted password to establish remote administrative access, creating a complete compromise scenario that allows for arbitrary code execution, data exfiltration, and further network infiltration. The attack vector demonstrates how legacy systems with end-of-life support can become persistent security threats, as the vulnerability exists in the device firmware itself rather than being a transient network issue.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates a persistent backdoor for attackers to maintain long-term access to network infrastructure. This represents a significant concern for organizations that may have deployed these devices in critical network segments, as the vulnerability allows for unauthorized remote access without requiring sophisticated attack techniques or social engineering. The fact that the MF910S reached end-of-service on October 23, 2019, means that no security updates or patches were available to address this weakness, leaving organizations with no remediation path for the identified vulnerability. This scenario exemplifies the risks associated with maintaining legacy network equipment and demonstrates how organizations must implement proper end-of-life management strategies to prevent the deployment of unsupported devices. The vulnerability's exploitation directly aligns with ATT&CK technique T1075 (Pass the Hash) and T1021.001 (Remote Services: Telnet), as it enables credential-based lateral movement and remote access to the compromised system.
Organizations that continue to operate devices with this vulnerability face significant risk exposure, particularly in environments where these devices may be connected to critical network infrastructure or contain sensitive operational data. The recommended mitigation strategy from ZTE emphasizes transitioning to newer product lines that offer enhanced security features and proper ongoing support, which aligns with industry standards for secure network device management and lifecycle planning. This vulnerability serves as a reminder of the importance of implementing comprehensive device inventory management and regular security assessments to identify and remediate legacy equipment that may pose ongoing security risks. The lack of available patches for this end-of-life product underscores the necessity for organizations to maintain robust security policies that include regular device lifecycle management and timely retirement of unsupported systems to prevent exploitation of known vulnerabilities.