CVE-2018-3919 in SmartThings Hub STH-ETH-250
Summary
by MITRE
An exploitable stack-based buffer overflow vulnerability exists in the retrieval of database fields in video-core's HTTP server of Samsung SmartThings Hub STH-ETH-250 devices with firmware version 0.20.17. The video-core process insecurely extracts the fields from the "clips" table of its SQLite database, leading to a buffer overflow on the stack. An attacker can send a series of HTTP requests to trigger this vulnerability.
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Analysis
by VulDB Data Team • 05/04/2023
The vulnerability identified as CVE-2018-3919 represents a critical stack-based buffer overflow within the video-core HTTP server component of Samsung SmartThings Hub STH-ETH-250 devices. This flaw exists in firmware version 0.20.17 and specifically affects how the system processes database field retrieval operations from the SQLite database. The vulnerability stems from insecure handling of data extraction from the "clips" table, creating a condition where unbounded data can overwrite adjacent stack memory locations. The attack vector requires remote exploitation through HTTP requests, making it particularly dangerous as it can be triggered without physical access to the device. This vulnerability falls under the CWE-121 stack-based buffer overflow category, which is classified as a fundamental memory safety issue that has been historically exploited in numerous security incidents. The attack technique aligns with ATT&CK tactics involving command and control operations and remote code execution, as the overflow could potentially allow an attacker to execute arbitrary code on the affected device.
The technical implementation of this vulnerability involves the video-core process performing unsafe string operations when extracting field data from the SQLite database. When processing HTTP requests that access the clips table, the system fails to properly validate or limit the size of data being copied to stack buffers. This insecure data handling creates a scenario where an attacker can craft malicious HTTP requests containing oversized field data that exceeds the allocated stack buffer space. The overflow occurs during the data retrieval phase when the system attempts to copy database field contents into local stack variables without proper bounds checking. The vulnerability demonstrates poor input validation practices and inadequate memory management, which are common root causes for buffer overflow exploits. The specific nature of the flaw suggests that the system uses functions like strcpy or sprintf without proper size constraints, making it susceptible to attacks that manipulate the data flow to exceed buffer boundaries.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it represents a potential gateway for complete device compromise. An attacker who successfully exploits this vulnerability could gain unauthorized access to the SmartThings Hub, potentially allowing for surveillance of home networks, modification of security settings, or use of the device as a pivot point for attacking other systems on the local network. The device serves as a central hub for home automation and security systems, making it an attractive target for attackers seeking persistent access to residential environments. The remote exploitation capability means that attackers do not require physical proximity to the device, significantly expanding the attack surface and making the vulnerability particularly concerning for residential security systems. The consequences could include unauthorized monitoring of smart home activities, potential data breaches, and compromise of other connected IoT devices within the network ecosystem.
Mitigation strategies for CVE-2018-3919 should focus on both immediate remediation and long-term security improvements. The most effective immediate solution involves updating the firmware to a version that properly validates database field sizes and implements proper bounds checking during data extraction operations. Samsung should provide security patches that address the specific buffer overflow conditions in the video-core process. Network-level mitigations include implementing firewall rules to restrict HTTP access to the SmartThings Hub, particularly if the device is not actively needed for remote access. The security community should also consider implementing intrusion detection systems that monitor for unusual HTTP request patterns that might indicate exploitation attempts. Additionally, users should be advised to disable unnecessary remote access features and ensure that the device operates within a segmented network environment. Organizations deploying these devices should conduct regular security assessments and maintain updated inventory records of all connected IoT devices to quickly identify and remediate similar vulnerabilities across their deployment. The vulnerability highlights the importance of secure coding practices and the need for robust input validation in embedded systems, particularly those handling database operations in security-critical environments.