CVE-2018-3897 in SmartThings Hub
Summary
by MITRE
An exploitable buffer overflow vulnerabilities exist in the /cameras/XXXX/clips handler of video-core's HTTP server of Samsung SmartThings Hub with Firmware version 0.20.17. The video-core process incorrectly extracts fields from a user-controlled JSON payload, leading to a buffer overflow on the stack. The strncpy call overflows the destination buffer, which has a size of 52 bytes. An attacker can send an arbitrarily long "callbackUrl" value in order to exploit this vulnerability.
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Analysis
by VulDB Data Team • 05/08/2023
The vulnerability identified as CVE-2018-3897 represents a critical buffer overflow flaw within the Samsung SmartThings Hub's video-core HTTP server component. This security weakness resides in the /cameras/XXXX/clips handler functionality where the system processes user-supplied JSON payloads without adequate input validation. The affected firmware version 0.20.17 demonstrates a fundamental failure in memory management practices that creates an exploitable condition for remote attackers. The vulnerability specifically manifests when the video-core process attempts to parse and extract data from incoming JSON structures, particularly focusing on the callbackUrl parameter which serves as the primary attack vector. This flaw falls under the category of CWE-121 Stack-based Buffer Overflow, a well-documented weakness that has been consistently exploited in various embedded systems and network services.
The technical execution of this vulnerability relies on improper string handling mechanisms within the application's memory management architecture. During the processing of the JSON payload, the system employs a strncpy function call that fails to properly validate the length of the incoming callbackUrl value against the predetermined destination buffer size of 52 bytes. This mismatch creates a condition where an attacker can provide an arbitrarily long string that exceeds the allocated buffer space, causing the stack to overflow and potentially allowing arbitrary code execution. The vulnerability's exploitation requires minimal privileges since it operates within the context of the HTTP server process, which typically runs with elevated permissions to manage video capture and network communication functions. The flaw demonstrates poor input sanitization practices and highlights the absence of proper bounds checking mechanisms that should be implemented in any security-conscious application handling external data inputs.
The operational impact of CVE-2018-3897 extends beyond simple denial of service conditions, presenting significant risks to the overall security posture of Samsung SmartThings Hub deployments. Remote attackers capable of reaching the affected HTTP server can potentially execute malicious code with the privileges of the video-core process, which may include access to network interfaces, camera controls, and other embedded system functionalities. This vulnerability directly aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, as the successful exploitation could enable attackers to gain unauthorized access to the underlying system resources. The attack surface is particularly concerning given that SmartThings Hubs are typically deployed in residential and commercial environments where they maintain persistent network connections and may have access to sensitive personal data. The vulnerability's exploitation could result in persistent surveillance capabilities, unauthorized data exfiltration, or use as a pivot point for attacking other networked devices within the same ecosystem.
Mitigation strategies for CVE-2018-3897 should prioritize immediate firmware updates from Samsung, as this vulnerability was addressed through subsequent security patches that properly validate input lengths and implement appropriate bounds checking. Network administrators should consider implementing firewall rules that restrict access to the affected HTTP endpoints, particularly limiting exposure to internal networks only where necessary. Additional protective measures include deploying intrusion detection systems that monitor for unusual JSON payload patterns and implementing strict input validation at network boundaries. The vulnerability serves as a reminder of the importance of secure coding practices in embedded systems, particularly regarding buffer management and input validation. Organizations should conduct comprehensive security assessments of their SmartThings deployments and consider isolating these devices on separate network segments to limit potential lateral movement. The incident also underscores the necessity for regular firmware updates and security monitoring to address vulnerabilities in IoT devices that may remain unpatched for extended periods, as highlighted in industry best practices from NIST and ISO/IEC 27001 standards for information security management.