CVE-2018-3911 in SmartThings Hub STH-ETH-250
Summary
by MITRE
An exploitable HTTP header injection vulnerability exists in the remote servers of Samsung SmartThings Hub STH-ETH-250 - Firmware version 0.20.17. The hubCore process listens on port 39500 and relays any unauthenticated message to SmartThings' remote servers, which insecurely handle JSON messages, leading to partially controlled requests generated toward the internal video-core process. An attacker can send an HTTP request to trigger this vulnerability.
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Analysis
by VulDB Data Team • 05/04/2023
The vulnerability identified as CVE-2018-3911 represents a critical HTTP header injection flaw within the Samsung SmartThings Hub STH-ETH-250 device firmware version 0.20.17. This security weakness resides in the hubCore process that operates on port 39500, creating a pathway for malicious actors to manipulate communication flows between the device and SmartThings' remote infrastructure. The vulnerability stems from inadequate input validation and sanitization within the HTTP header processing mechanisms, allowing attackers to inject malicious headers that can be interpreted by the remote servers.
The technical exploitation of this vulnerability occurs through the relay mechanism established by the hubCore process, which forwards unauthenticated messages to SmartThings' remote servers without proper validation. This design flaw enables attackers to craft malicious HTTP requests that can influence the behavior of the internal video-core process, which operates in a different security context within the device's architecture. The vulnerability specifically targets the insecure handling of JSON messages that pass through the HTTP communication layer, creating a chain reaction where attacker-controlled data can manipulate internal processes.
The operational impact of this vulnerability extends beyond simple header injection, as it creates potential for more sophisticated attacks including man-in-the-middle scenarios and unauthorized access to internal device functions. The attack surface is particularly concerning because the vulnerability affects a network-connected IoT device that serves as a central hub for home automation systems, potentially providing attackers with access to other connected devices within the network. The unauthenticated nature of the message relay means that any attacker with network access can exploit this vulnerability without requiring legitimate credentials.
Security professionals should note that this vulnerability aligns with CWE-113, which describes improper neutralization of characters or elements within HTTP headers, and demonstrates characteristics consistent with ATT&CK technique T1071.004 for application layer protocol: DNS. The lack of proper input sanitization creates a persistent risk that can be exploited across multiple sessions and network configurations. Organizations should implement network segmentation to isolate IoT devices from critical systems and deploy intrusion detection systems to monitor for suspicious HTTP header patterns. Additionally, the vulnerability highlights the importance of secure coding practices in embedded systems and the need for comprehensive input validation mechanisms.
Mitigation strategies should include immediate firmware updates from Samsung to address the underlying implementation flaws, network-level filtering to restrict access to port 39500, and implementation of proper authentication mechanisms for device management interfaces. The vulnerability also underscores the necessity of conducting security assessments for IoT devices and implementing secure communication protocols that prevent header injection attacks. Organizations should establish monitoring procedures to detect anomalous communication patterns that might indicate exploitation attempts and maintain up-to-date threat intelligence for IoT-specific vulnerabilities.