CVE-2018-3902 in SmartThings Hub STH-ETH-250
Summary
by MITRE
An exploitable buffer overflow vulnerability exists in the camera "replace" feature of video-core's HTTP server of Samsung SmartThings Hub STH-ETH-250 devices with firmware version 0.20.17. The video-core process incorrectly extracts the URL 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-2018-3902 represents a critical buffer overflow flaw within the Samsung SmartThings Hub STH-ETH-250 device firmware version 0.20.17. This issue resides in the video-core HTTP server component that handles camera-related operations, specifically the "replace" feature functionality. The vulnerability manifests when the system processes user-controlled JSON payloads through HTTP requests, creating a dangerous condition where memory corruption can occur. The flaw is particularly concerning as it affects a smart home hub device that serves as a central control point for various IoT devices within residential and commercial environments, potentially providing attackers with persistent access to otherwise secured networks.
The technical root cause of this vulnerability stems from improper input validation within the video-core process that manages URL field extraction from JSON payloads. When an attacker crafts a malicious HTTP request containing a specially formatted JSON object with an oversized URL field, the system fails to properly bounds-check the input before copying it into a fixed-size stack buffer. This classic buffer overflow condition occurs because the implementation does not verify that the incoming data length fits within the allocated memory space, allowing subsequent data to overwrite adjacent memory locations. The stack-based nature of the overflow means that the attacker can potentially overwrite return addresses, saved registers, and other critical stack frame information, enabling arbitrary code execution or system crash conditions.
From an operational perspective, this vulnerability presents significant security implications for users of Samsung SmartThings Hub devices, particularly those with internet-facing configurations. The attack vector requires only a simple HTTP request to be sent to the device, making exploitation relatively straightforward and accessible to threat actors with basic network reconnaissance capabilities. Successful exploitation could allow attackers to execute arbitrary code with the privileges of the video-core process, potentially leading to complete device compromise, data exfiltration, or use of the device as a pivot point for attacking other systems within the local network. The vulnerability affects the device's core functionality, potentially disrupting camera operations and creating persistent backdoors for attackers. This flaw directly aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a critical weakness in the device's input handling mechanisms.
The impact extends beyond individual device compromise to encompass broader network security implications, as the SmartThings Hub typically serves as a central coordinator for multiple IoT devices within home and business environments. An attacker who successfully exploits this vulnerability could potentially gain access to connected cameras, sensors, and other smart home devices, creating a comprehensive surveillance and control capability. Network-based attacks leveraging this vulnerability could occur without requiring physical access to the device, making it particularly dangerous in environments where such devices are deployed. The vulnerability's presence in firmware version 0.20.17 indicates that it was likely present across multiple device generations, potentially affecting a substantial user base. Security professionals should consider this vulnerability as part of broader ATT&CK framework considerations, particularly under the T1059.007 technique for command and scripting interpreter usage, as successful exploitation could enable attackers to execute malicious commands on the compromised device.
Mitigation strategies for this vulnerability should include immediate firmware updates from Samsung to address the buffer overflow condition in the video-core HTTP server implementation. Network segmentation and firewall rules should be implemented to restrict access to the SmartThings Hub's HTTP interfaces, particularly when the device is connected to internet-facing networks. Regular monitoring for unusual network traffic patterns or unauthorized access attempts should be conducted to detect potential exploitation attempts. Additionally, users should disable unnecessary services and features on the device, particularly those that are not required for normal operation. The vulnerability serves as a reminder of the critical importance of input validation and memory safety in embedded systems, particularly those handling user-controllable data in IoT environments where device compromise can have far-reaching security implications. Organizations should implement comprehensive vulnerability management programs to address similar issues in other networked devices and ensure that firmware updates are applied promptly to maintain device security posture.