CVE-2018-3914 in SmartThings Hub STH-ETH-250
Summary
by MITRE
An exploitable stack-based buffer overflow vulnerability exists in the retrieval of database fields in the video-core HTTP server of the Samsung SmartThings Hub STH-ETH-250 - Firmware version 0.20.17. The strcpy call overflows the destination buffer, which has a size of 2000 bytes. An attacker can send an arbitrarily long "sessionToken" value in order to exploit this vulnerability.
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Analysis
by VulDB Data Team • 05/17/2023
The vulnerability identified as CVE-2018-3914 represents a critical stack-based buffer overflow in the video-core HTTP server component of Samsung SmartThings Hub STH-ETH-250 devices running firmware version 0.20.17. This flaw resides within the database field retrieval mechanism, specifically manifesting when processing user-supplied session tokens through an unsafe strcpy function call. The buffer size limitation of 2000 bytes creates a predictable overflow condition that can be systematically exploited by malicious actors. The vulnerability's exploitation potential stems from the device's web server functionality, which processes HTTP requests containing session tokens without adequate input validation or bounds checking, making it susceptible to arbitrary code execution.
The technical implementation of this vulnerability follows a classic stack buffer overflow pattern where the strcpy function copies data from the source buffer to a destination buffer without verifying the source length against the destination capacity. This insecure coding practice directly maps to CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows data to overwrite adjacent stack memory. The attack vector requires an attacker to craft a malicious HTTP request containing an excessively long sessionToken parameter that exceeds the 2000-byte buffer limit. When the system processes this request, the strcpy operation continues copying data beyond the allocated buffer boundaries, corrupting the stack and potentially allowing an attacker to overwrite return addresses, function pointers, or other critical stack variables. This memory corruption can lead to arbitrary code execution, privilege escalation, or complete system compromise, depending on the execution environment and memory layout.
The operational impact of this vulnerability extends beyond simple exploitation, as it affects the security posture of smart home ecosystems that rely on Samsung SmartThings Hub devices for network connectivity and IoT device management. The vulnerability can be exploited remotely without authentication requirements, making it particularly dangerous in environments where these devices are accessible from untrusted networks. An attacker who successfully exploits this vulnerability can gain full control over the hub device, potentially enabling them to monitor network traffic, manipulate connected IoT devices, or use the compromised device as a pivot point for further attacks within the local network. The device's role as a central hub for smart home automation makes this a particularly attractive target, as the compromise could provide access to sensitive personal data, home security systems, and other connected devices. The vulnerability's presence in firmware version 0.20.17 indicates that Samsung had not yet addressed this specific flaw, leaving users exposed to potential exploitation through well-established attack methodologies documented in various security frameworks.
Mitigation strategies for CVE-2018-3914 should prioritize immediate firmware updates from Samsung, as the company likely released patches addressing this specific buffer overflow condition. Network segmentation and access controls can provide temporary protection by limiting exposure to trusted networks and reducing the attack surface. Implementing network monitoring solutions that detect anomalous sessionToken lengths or malformed HTTP requests can help identify exploitation attempts. Security professionals should also consider disabling unnecessary HTTP services on the device when possible, as reducing attack surface minimizes the likelihood of successful exploitation. The vulnerability highlights the importance of secure coding practices and input validation, particularly when handling user-supplied data in embedded systems. Organizations should implement regular security assessments of IoT devices and maintain updated vulnerability management procedures to address similar issues proactively. The incident underscores the need for robust software supply chain security measures and emphasizes the critical role of proper bounds checking in preventing buffer overflow vulnerabilities that can lead to system compromise.