CVE-2018-3872 in SmartThings Hub STH-ETH-250
Summary
by MITRE
An exploitable buffer overflow vulnerability exists in the credentials handler of video-core's HTTP server of Samsung SmartThings Hub STH-ETH-250 - Firmware version 0.20.17. The video-core process incorrectly extracts the videoHostUrl field from a user-controlled JSON payload, leading to a buffer overflow on the stack. An attacker can send an HTTP request to trigger this vulnerability.
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Analysis
by VulDB Data Team • 05/04/2023
The vulnerability identified as CVE-2018-3872 represents a critical buffer overflow flaw within the video-core HTTP server component of Samsung SmartThings Hub STH-ETH-250 devices running firmware version 0.20.17. This issue resides in the credentials handler module where the system processes user-controlled JSON payloads containing videoHostUrl fields. The flaw demonstrates characteristics consistent with CWE-121, stack-based buffer overflow, where insufficient bounds checking allows malicious input to overwrite adjacent stack memory regions. The vulnerability is particularly concerning as it operates within a network-facing HTTP server that processes external requests, making it directly exploitable by remote attackers without physical access requirements.
The technical exploitation mechanism involves the video-core process failing to properly validate or limit the length of the videoHostUrl field extracted from JSON input. When an attacker crafts a malicious HTTP request containing an excessively long videoHostUrl value, the system's insufficient input validation leads to stack memory corruption. This overflow can overwrite return addresses, function pointers, and other critical stack data structures, potentially enabling arbitrary code execution or system crashes. The vulnerability's remote exploitability stems from the fact that the affected device listens on network ports and accepts HTTP requests from external sources, eliminating the need for local network access or physical presence. The stack-based nature of the overflow aligns with ATT&CK technique T1203, which involves manipulating program execution through stack corruption.
From an operational perspective, this vulnerability poses significant risks to smart home environments as it allows remote attackers to compromise the entire Samsung SmartThings Hub device. Successful exploitation could enable attackers to gain full control over the hub's operations, potentially allowing them to access or manipulate all connected smart home devices, steal sensitive authentication credentials, or establish persistent backdoors within the home network. The impact extends beyond individual device compromise to threaten the broader security posture of connected home ecosystems, as the hub typically serves as a central coordinator for multiple IoT devices. Organizations and individuals using these devices face potential data breaches, unauthorized access to personal information, and possible use of compromised devices as launching points for attacks against other networked systems.
Mitigation strategies for CVE-2018-3872 should prioritize immediate firmware updates from Samsung, which would contain patches addressing the buffer overflow in the video-core HTTP server component. Network segmentation and firewall rules should be implemented to restrict access to the hub's HTTP ports, limiting exposure to untrusted networks. Additional protective measures include disabling unnecessary HTTP services, implementing intrusion detection systems to monitor for suspicious HTTP requests, and conducting regular security assessments of the smart home network infrastructure. Organizations should also consider deploying network access control measures that prevent unauthorized devices from connecting to the home network, reducing the attack surface available to potential exploiters. The vulnerability highlights the importance of secure coding practices in IoT devices and the critical need for input validation and bounds checking in all network-facing components.