CVE-2018-3878 in SmartThings Hub STH-ETH-250
Summary
by MITRE
Multiple exploitable buffer overflow vulnerabilities exist in the credentials handler of video-core's HTTP server of Samsung SmartThings Hub STH-ETH-250 devices 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. A strncpy overflows the destination buffer, which has a size of 16 bytes. An attacker can send an arbitrarily long "region" value in order to exploit this vulnerability.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 05/04/2023
The CVE-2018-3878 vulnerability represents a critical buffer overflow flaw within the video-core HTTP server component of Samsung SmartThings Hub STH-ETH-250 devices. This vulnerability stems from improper input validation within the credentials handler module, where the system fails to adequately sanitize user-controlled JSON payloads before processing them. The flaw manifests when the video-core process attempts to extract and store data from the JSON structure, specifically targeting the region field parameter. The underlying technical implementation uses a strncpy function to copy user-supplied data into a destination buffer that is only 16 bytes in size, creating an exploitable condition where any input exceeding this limit will overflow the allocated memory space.
The operational impact of this vulnerability extends beyond simple memory corruption, as it provides attackers with potential remote code execution capabilities within the device's operating environment. The buffer overflow occurs on the stack, which means that attackers can manipulate the program's execution flow by overwriting return addresses and function pointers stored in memory. This type of vulnerability is classified under CWE-121 as a stack-based buffer overflow, which directly enables attackers to inject and execute malicious code within the device's memory space. The specific exploitation vector involves sending a crafted JSON payload containing an excessively long "region" value that exceeds the 16-byte buffer capacity, allowing for arbitrary code execution in the context of the video-core process.
The security implications of this vulnerability are particularly severe given the nature of smart home devices and their network connectivity. Samsung SmartThings Hubs serve as central control points for home automation systems, making them attractive targets for attackers seeking persistent access to residential networks. The vulnerability exists in firmware version 0.20.17, indicating that this was a known issue that required firmware updates to address. From an adversarial perspective, this flaw aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation would allow attackers to execute arbitrary commands on the device. The vulnerability also maps to ATT&CK technique T1071.004 for application layer protocol, since it exploits HTTP server functionality to deliver malicious payloads.
Mitigation strategies for CVE-2018-3878 should prioritize immediate firmware updates from Samsung to address the root cause of the buffer overflow. Network segmentation and access controls should be implemented to limit exposure of these devices to untrusted networks, as recommended in NIST SP 800-53 security controls. The device should be configured to disable unnecessary services and reduce attack surface where possible. Security monitoring should include detection of anomalous JSON payload patterns and unusual network traffic originating from the affected device. Additionally, implementing input validation mechanisms at the application layer to enforce maximum length constraints on all user-supplied data fields would provide defense-in-depth protection against similar vulnerabilities. Organizations should also consider deploying network intrusion detection systems capable of identifying and blocking malicious payloads targeting known buffer overflow patterns in HTTP server implementations.