CVE-2017-20222 in SDT-CS3B1
Summary
by MITRE • 03/16/2026
Telesquare SKT LTE Router SDT-CS3B1 software version 1.2.0 contains an unauthenticated remote reboot vulnerability that allows attackers to trigger device reboot without authentication. Attackers can send POST requests to the lte.cgi endpoint with the Command=Reboot parameter to cause denial of service by forcing the router to restart.
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Analysis
by VulDB Data Team • 03/16/2026
The vulnerability identified as CVE-2017-20222 affects the Telesquare SKT LTE Router model SDT-CS3B1 running software version 1.2.0, representing a critical security weakness that undermines the device's operational integrity. This flaw resides within the router's web management interface, specifically at the lte.cgi endpoint which handles various system commands without requiring proper authentication mechanisms. The vulnerability manifests as a lack of access control validation, allowing any remote attacker to execute privileged operations through simple HTTP POST requests.
The technical implementation of this vulnerability stems from the router's failure to implement proper authentication checks before processing system commands. When an attacker sends a POST request to the lte.cgi endpoint containing the Command=Reboot parameter, the device processes this request without verifying the sender's credentials or authorization status. This design flaw directly violates fundamental security principles of access control and privilege management, creating an unauthenticated command execution pathway that can be exploited from any network location.
From an operational impact perspective, this vulnerability enables attackers to perform denial of service attacks against the affected routers, effectively disrupting network connectivity for devices relying on the LTE connection. The remote reboot capability can be leveraged to repeatedly restart the device, potentially causing extended network outages that impact business operations, emergency services, or critical infrastructure depending on the deployment environment. The attack requires minimal technical expertise and can be executed through simple web request tools or automated scripts, making it particularly dangerous for widespread exploitation.
This vulnerability aligns with CWE-306, which describes the improper handling of authentication in software systems, and represents a clear violation of the principle of least privilege. The attack vector follows the ATT&CK technique T1499.004 for network denial of service, specifically targeting network infrastructure components to disrupt service availability. The vulnerability also corresponds to CWE-284, which addresses improper access control mechanisms, as the device fails to properly validate user credentials before executing system-level commands.
Security mitigation strategies should prioritize immediate firmware updates from the vendor to address the authentication bypass flaw, while network administrators should implement firewall rules to restrict access to the affected lte.cgi endpoint. Additionally, organizations should consider network segmentation to limit exposure and deploy intrusion detection systems to monitor for suspicious POST requests targeting the vulnerable endpoint. The most effective long-term solution involves ensuring all network devices implement robust authentication mechanisms and proper input validation to prevent unauthorized command execution. Organizations should also conduct regular security assessments to identify similar authentication bypass vulnerabilities in their network infrastructure and ensure proper patch management processes are in place to address such issues promptly.