CVE-2018-3896 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 "correlationId" value in order to exploit this vulnerability.
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Analysis
by VulDB Data Team • 05/08/2023
The vulnerability identified as CVE-2018-3896 represents a critical buffer overflow flaw within the Samsung SmartThings Hub's video-core HTTP server component. This issue resides in the /cameras/XXXX/clips handler where the system processes incoming JSON payloads from remote clients. The vulnerability specifically affects firmware version 0.20.17 of the SmartThings Hub, making it a targeted concern for users operating this particular software version. The flaw demonstrates how insufficient input validation can lead to severe security implications in IoT devices that serve as central hubs for home automation systems.
The technical root cause of this vulnerability stems from improper handling of user-controlled data within the video-core process. When processing JSON payloads, the system utilizes a strncpy function to copy data into a destination buffer that is only 52 bytes in size. This hardcoded buffer size creates a direct pathway for overflow conditions when the source data exceeds the allocated space. The vulnerability is particularly dangerous because it allows attackers to manipulate the "correlationId" field within the JSON payload to inject arbitrarily long strings. The strncpy function, while generally safer than strcpy, still fails to prevent buffer overflows when the source length exceeds the specified destination size parameter, creating a classic stack-based buffer overflow scenario.
The operational impact of this vulnerability extends beyond simple denial of service conditions to encompass potential remote code execution capabilities. An attacker exploiting this buffer overflow could overwrite critical stack memory locations including return addresses and function pointers, potentially allowing for arbitrary code execution on the affected device. This presents a significant risk to home network security since the SmartThings Hub serves as a central control point for numerous connected devices. The vulnerability affects not just the device itself but could potentially provide attackers with access to the entire smart home ecosystem managed by the hub. The attack surface is particularly concerning given that the vulnerability exists in a handler that processes camera clip data, suggesting potential access to surveillance footage and related metadata.
Mitigation strategies for CVE-2018-3896 should prioritize immediate firmware updates from Samsung to address the underlying buffer overflow issue. Network segmentation and access controls should be implemented to limit exposure of the SmartThings Hub to untrusted networks. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which is classified under the broader category of CWE-122 Heap-based Buffer Overflow, both of which represent fundamental security weaknesses in memory management. From an ATT&CK framework perspective, this vulnerability maps to T1203 Exploitation for Client Execution and T1059 Command and Scripting Interpreter, as successful exploitation could enable attackers to execute malicious commands on the device. Organizations should also consider implementing network monitoring to detect unusual JSON payload patterns that might indicate exploitation attempts, and establish robust patch management procedures to ensure all IoT devices receive timely security updates.