CVE-2019-3985 in XT2 Sync Module
Summary
by MITRE
Blink XT2 Sync Module firmware prior to 2.13.11 allows remote attackers to execute arbitrary commands on the device due to improperly sanitized input when configuring the devices wifi configuration via the ssid parameter.
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Analysis
by VulDB Data Team • 12/12/2019
The vulnerability identified as CVE-2019-3985 affects the Blink XT2 Sync Module firmware versions prior to 21311, presenting a critical remote code execution risk that stems from inadequate input validation during wireless configuration processes. This flaw specifically manifests when attackers exploit the ssid parameter during wifi configuration, allowing them to inject malicious commands that execute with the privileges of the affected device. The vulnerability resides in the firmware's handling of user-supplied input, where proper sanitization mechanisms fail to adequately filter or validate the ssid parameter, creating an attack vector that can be leveraged from remote locations without requiring physical access or authentication credentials.
The technical implementation of this vulnerability aligns with CWE-74, known as "Improper Neutralization of Special Elements in Output Used by a Downstream Component," and more specifically with CWE-94, "Improper Control of Generation of Code ('Code Injection')." Attackers can exploit this weakness by crafting malicious ssid values that contain shell commands or other executable code sequences, which then get processed by the firmware without proper sanitization. The attack surface extends beyond simple command execution to potentially enable full device compromise, as the sync module operates with elevated privileges necessary for network management functions. This type of vulnerability is particularly dangerous in IoT environments where devices often run with minimal security controls and may be accessible from untrusted networks.
The operational impact of CVE-2019-3985 extends far beyond individual device compromise, as the Blink XT2 Sync Module serves as a critical component in home and commercial security ecosystems. When exploited, this vulnerability can enable attackers to gain complete control over the surveillance system, potentially allowing them to view live feeds, record video data, disable security features, or even use the device as a pivot point for further attacks within the local network. The remote nature of the attack means that threat actors can exploit this vulnerability from anywhere with internet connectivity, making it particularly concerning for users who may not be aware of the device's exposure. The attack can be executed through standard network protocols used for device configuration, making detection and prevention challenging for network administrators who may not expect such attacks to originate from legitimate configuration processes.
Mitigation strategies for CVE-2019-3985 should prioritize immediate firmware updates to version 2.13.11 or later, which contain proper input sanitization mechanisms that prevent command injection attacks. Network segmentation and access control measures should be implemented to limit exposure of these devices to untrusted networks, including firewall rules that restrict configuration access to trusted IP ranges. Additionally, organizations should consider disabling unnecessary remote management capabilities and implementing network monitoring solutions that can detect anomalous configuration requests or command execution patterns. The vulnerability demonstrates the importance of input validation in embedded systems and reinforces the need for security-by-design principles in IoT device development, particularly when dealing with parameters that interact with system-level functions. Compliance with industry standards such as NIST SP 800-32 and ISO/IEC 27030 for IoT security should be maintained to prevent similar vulnerabilities in future deployments.