CVE-2018-3908 in SmartThings Hub STH-ETH-250
Summary
by MITRE
An exploitable vulnerability exists in the REST parser of video-core's HTTP server of the Samsung SmartThings Hub STH-ETH-250-Firmware version 0.20.17. The video-core process incorrectly handles pipelined HTTP requests, which allows successive requests to overwrite the previously parsed HTTP method, URL and body. With the implementation of the on_body callback, defined by sub_41734, an attacker can send an HTTP request to trigger this vulnerability.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 05/06/2023
The vulnerability identified as CVE-2018-3908 represents a critical buffer overflow condition within the REST parser component of Samsung SmartThings Hub STH-ETH-250 firmware version 0.20.17. This issue manifests in the video-core HTTP server process where the system fails to properly handle pipelined HTTP requests, creating a scenario where subsequent requests can overwrite previously parsed HTTP method, URL, and body data. The root cause lies in the improper management of request parsing state within the HTTP server implementation, specifically affecting how the system processes multiple requests submitted in rapid succession. The vulnerability is particularly concerning because it operates at the HTTP protocol level within the embedded system, allowing for potential exploitation through carefully crafted network traffic.
The technical flaw stems from the video-core process's inadequate handling of HTTP request pipelining, where the parser does not properly isolate state information between successive requests. When the on_body callback function sub_41734 is invoked, it triggers a condition where the attacker can manipulate the parsing state to overwrite critical request parameters. This behavior creates a memory corruption scenario where the HTTP method, URL, and body data from one request can be overwritten by data from subsequent requests, leading to unpredictable application behavior. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, though the specific implementation involves heap memory manipulation through improper state management in the HTTP request processing pipeline. The flaw demonstrates poor input validation and state handling practices that are common in embedded systems where resource constraints may lead to simplified parsing logic.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it creates potential for arbitrary code execution within the SmartThings Hub environment. Attackers can exploit this condition to manipulate the device's behavior through crafted HTTP requests that overwrite critical parsing state information. The vulnerability is particularly dangerous in IoT environments where these hubs serve as central control points for home automation systems, potentially allowing attackers to gain unauthorized access to connected devices and disrupt smart home operations. The exploitation requires minimal network access and can be performed remotely, making it a significant concern for IoT security. This vulnerability aligns with ATT&CK technique T1210 for exploiting known vulnerabilities, specifically targeting the device's HTTP server implementation. The impact is further amplified by the fact that the SmartThings Hub typically operates in residential environments where physical security is often minimal, providing attackers with easy access points for exploitation.
Mitigation strategies for CVE-2018-3908 should focus on firmware updates from Samsung, which would address the underlying parsing logic and state management issues. Network segmentation and access controls should be implemented to limit exposure to this vulnerability, particularly in environments where the SmartThings Hub is accessible from untrusted networks. The implementation of HTTP request rate limiting and validation mechanisms can help prevent exploitation attempts by limiting the ability to send multiple pipelined requests in a manner that triggers the vulnerability. Security monitoring should be enhanced to detect unusual HTTP request patterns that might indicate exploitation attempts, and network traffic analysis should be employed to identify potential attackers. Organizations should also consider disabling unnecessary HTTP services on the device when possible, and implementing intrusion detection systems that can monitor for exploitation attempts targeting this specific vulnerability. The vulnerability highlights the importance of proper input validation and state management in embedded systems, particularly those serving as central hubs in IoT environments where security failures can have widespread consequences.