CVE-2017-20221 in SDT-CS3B1
Summary
by MITRE • 03/16/2026
Telesquare SKT LTE Router SDT-CS3B1 version 1.2.0 contains a cross-site request forgery vulnerability that allows authenticated attackers to execute arbitrary system commands by exploiting missing request validation. Attackers can craft malicious web pages that perform administrative actions when visited by logged-in users, enabling command execution with router privileges.
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Analysis
by VulDB Data Team • 03/16/2026
The vulnerability identified as CVE-2017-20221 affects the Telesquare SKT LTE Router SDT-CS3B1 model running firmware version 1.2.0, representing a critical cross-site request forgery flaw that fundamentally compromises the device's security posture. This vulnerability resides within the router's web-based administrative interface, where insufficient input validation and missing anti-CSRF protections create an exploitable condition that allows authenticated attackers to execute arbitrary system commands. The flaw specifically manifests when the router fails to properly validate incoming requests, particularly those originating from web pages crafted by malicious actors, thereby enabling unauthorized command execution with the privileges of the authenticated user.
The technical implementation of this vulnerability stems from the absence of proper request validation mechanisms within the router's web administration framework, which aligns with CWE-352 - Cross-Site Request Forgery. The router's authentication system correctly validates user credentials, but once authenticated, the web interface lacks anti-CSRF tokens or other protective measures that would prevent malicious pages from submitting requests on behalf of logged-in users. This design flaw allows attackers to construct malicious web pages containing embedded requests that, when visited by an authenticated user, automatically execute administrative functions without requiring additional authentication. The vulnerability is particularly dangerous because it operates at the system level, enabling command execution with the same privileges as the authenticated user, which in many cases corresponds to administrative privileges within the router's operating system.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it provides attackers with a persistent foothold within network infrastructure that can be leveraged for more sophisticated attacks. An attacker who successfully exploits this vulnerability can execute arbitrary commands on the router, potentially gaining access to network configuration settings, modifying firewall rules, redirecting traffic, or even installing persistent backdoors. The attack vector requires only that a logged-in user visits a malicious webpage, making it particularly insidious as it can be delivered through social engineering campaigns, compromised websites, or malicious email attachments. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1059 - Command and Scripting Interpreter and T1071 - Application Layer Protocol, where attackers can leverage compromised network devices to execute commands and establish persistence within target environments.
Mitigation strategies for CVE-2017-20221 should prioritize immediate firmware updates from the vendor, as the vulnerability is likely addressed through proper implementation of anti-CSRF measures and enhanced request validation. Network administrators should also implement network segmentation to limit the impact of potential exploitation, disable unnecessary administrative services, and monitor network traffic for suspicious command execution patterns. Additional protective measures include implementing web application firewalls to detect and block malicious requests, enforcing strict access controls for administrative interfaces, and conducting regular security assessments of network infrastructure devices. The vulnerability highlights the critical importance of input validation and anti-CSRF protections in web applications, particularly those managing privileged system functions, and demonstrates how seemingly simple implementation oversights can create significant security risks that persist across multiple network devices and potentially compromise entire network infrastructures.