CVE-2019-13402 in FCM-MB40
Summary
by MITRE
/usr/sbin/default.sh and /usr/apache/htdocs/cgi-bin/admin/hardfactorydefault.cgi on Dynacolor FCM-MB40 v1.2.0.0 devices implement an incomplete factory-reset process. A backdoor can persist because neither system accounts nor the set of services is reset.
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Analysis
by VulDB Data Team • 10/18/2023
The vulnerability identified as CVE-2019-13402 affects Dynacolor FCM-MB40 devices running firmware version 1.2.0.0 and exposes a critical flaw in the factory reset implementation. This issue resides in the system's default configuration scripts located at /usr/sbin/default.sh and /usr/apache/htdocs/cgi-bin/admin/hardfactorydefault.cgi paths. The incomplete factory reset process creates a persistent backdoor condition that undermines the device's security posture by failing to properly eliminate all system accounts and services during the reset operation.
This vulnerability represents a significant security weakness that aligns with CWE-696, which addresses incorrect behavior ordering that can lead to security flaws. The flaw occurs because the factory reset mechanism does not comprehensively wipe the system state, leaving behind active user accounts and running services that can be exploited by malicious actors. The incomplete reset process creates a scenario where unauthorized access can be maintained even after what should be a complete system restoration.
The operational impact of this vulnerability extends beyond simple access persistence, as it provides attackers with continued privileges and system capabilities that should have been eliminated during the reset process. Attackers who gain initial access to the device can leverage this backdoor to maintain long-term presence without requiring additional authentication or exploitation methods. This persistent access capability significantly increases the attack surface and allows for extended reconnaissance, data exfiltration, or further network infiltration activities.
From a cybersecurity perspective, this vulnerability directly impacts the principle of least privilege and system integrity by failing to properly implement the expected factory reset functionality. The issue creates a condition where system administrators cannot rely on the factory reset process to restore a clean system state, undermining trust in the device's security mechanisms. Organizations relying on these devices face potential compromise scenarios where attackers can maintain access through the persistent backdoor, potentially leading to complete network infiltration. The vulnerability also violates the NIST SP 800-53 security controls related to system access and configuration management, as proper system state restoration is not achieved.
Mitigation strategies should include immediate firmware updates from Dynacolor to address the incomplete reset implementation, along with manual verification of system accounts and services after any reset operations. Network segmentation and access controls should be implemented to limit the potential impact of compromised devices. Additionally, organizations should conduct comprehensive security assessments to identify any existing backdoor access and establish monitoring procedures to detect unauthorized system modifications. The ATT&CK framework's T1078 technique for Valid Accounts and T1566 for Phishing should be considered when developing defensive strategies against potential exploitation of this vulnerability.