CVE-2018-3865 in SmartThings Hub STH-ETH-250
Summary
by MITRE
An exploitable buffer overflow vulnerability exists in the Samsung WifiScan handler of video-core's HTTP server of Samsung SmartThings Hub STH-ETH-250 - Firmware version 0.20.17. The strcpy overflows the destination buffer, which has a size of 40 bytes. An attacker can send an arbitrarily long "cameraIp" value in order to exploit this vulnerability.
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Analysis
by VulDB Data Team • 05/17/2023
The vulnerability identified as CVE-2018-3865 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's WifiScan handler component, specifically manifesting as an insecure use of the strcpy function that lacks proper bounds checking. The flaw demonstrates a classic stack-based buffer overflow condition where a destination buffer of only 40 bytes is susceptible to being overwritten by arbitrarily long input data. This vulnerability affects the device's web interface functionality and exposes the underlying system to potential exploitation through crafted HTTP requests.
The technical implementation of this vulnerability stems from the improper handling of user-supplied input within the cameraIp parameter processing. When an attacker sends a specially crafted HTTP request containing an excessively long cameraIp value, the strcpy function blindly copies this data into a fixed 40-byte buffer without validating the source length. This primitive memory management error creates a predictable overflow condition that can overwrite adjacent memory locations including return addresses, stack canaries, and other critical program state information. The vulnerability maps directly to CWE-121 Stack-based Buffer Overflow, which is classified as a high-severity weakness in the Common Weakness Enumeration catalog. The attack vector is particularly concerning as it requires no authentication and can be executed through a simple HTTP request, making it highly accessible to remote attackers.
The operational impact of this vulnerability extends beyond simple denial of service conditions to encompass potential system compromise and unauthorized access to the SmartThings Hub's underlying network infrastructure. Successful exploitation could allow attackers to execute arbitrary code on the device, potentially enabling them to gain full control over the hub's operations, access connected IoT devices, or establish persistent backdoors within the home network. The SmartThings Hub serves as a central coordinator for numerous smart home devices, making this vulnerability particularly dangerous as it could provide attackers with access to an entire ecosystem of connected devices. This aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1071.004 for Application Layer Protocol specifically targeting HTTP traffic. The vulnerability's remote exploitability without authentication makes it a prime target for automated scanning and exploitation campaigns targeting IoT device fleets.
Mitigation strategies for CVE-2018-3865 should prioritize immediate firmware updates from Samsung to address the underlying buffer overflow condition. Network segmentation and firewall rules should be implemented to restrict access to the SmartThings Hub's HTTP interface from untrusted networks, while monitoring systems should be deployed to detect anomalous traffic patterns associated with exploitation attempts. The device should be configured to disable unnecessary services and features, particularly those that expose the vulnerable WifiScan handler functionality. Security professionals should implement regular vulnerability assessments and penetration testing to identify similar buffer overflow conditions in other firmware components, as the use of dangerous functions like strcpy without proper bounds checking represents a common pattern in embedded system development that requires systematic remediation. Additionally, network-based intrusion detection systems should be configured to alert on HTTP requests containing suspiciously long parameter values that could indicate exploitation attempts against similar vulnerabilities.