CVE-2018-3917 in SmartThings Hub STH-ETH-250
Summary
by MITRE
On Samsung SmartThings Hub STH-ETH-250 devices with firmware version 0.20.17, the video-core process insecurely extracts the fields from the "shard" table of its SQLite database, leading to a buffer overflow on the stack. An attacker can send an HTTP request to trigger this vulnerability. The strcpy call 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.
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Analysis
by VulDB Data Team • 05/04/2023
The vulnerability identified as CVE-2018-3917 affects Samsung SmartThings Hub STH-ETH-250 devices running firmware version 0.20.17, representing a critical stack-based buffer overflow flaw that resides within the video-core process component of the device's software architecture. This vulnerability stems from improper input validation and handling within the SQLite database processing logic, specifically when extracting data from the "shard" table. The flaw manifests through an insecure coding practice where the system uses the strcpy function without proper bounds checking, creating an exploitable condition that can be triggered remotely via HTTP requests. The destination buffer size of only 16 bytes creates an extremely limited space for data storage, making it highly susceptible to overflow conditions when processing user-supplied input. The vulnerability is particularly concerning as it operates within a network-accessible service that handles external requests, providing attackers with a clear attack surface that requires no physical access to the device.
The technical implementation of this vulnerability follows a classic buffer overflow pattern that maps directly to CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows data to overwrite adjacent memory locations. The attack vector involves sending an HTTP request containing an overly long "region" parameter value, which the video-core process then attempts to copy into a 16-byte buffer using strcpy. This function does not perform any size validation, allowing the copying of arbitrary-length data that exceeds the allocated buffer space. The overflow occurs on the stack, potentially overwriting return addresses, function pointers, or other critical control data structures. According to ATT&CK framework category T1203, this vulnerability represents a remote code execution opportunity that could be exploited through network-based attacks, while the technique aligns with T1068 which covers local privilege escalation and code execution through exploitation of software vulnerabilities.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it presents a significant security risk that could allow remote attackers to gain unauthorized control over affected SmartThings hubs. The device serves as a central hub for home automation systems, making it an attractive target for attackers seeking to compromise entire home networks. Successful exploitation could enable attackers to execute arbitrary code with the privileges of the video-core process, potentially leading to complete system compromise. The vulnerability affects a specific firmware version, indicating that Samsung may have addressed the issue in subsequent releases, but devices that remain unpatched continue to pose risks. The nature of the flaw suggests that attackers could potentially manipulate the device's behavior to monitor network traffic, modify automation rules, or use the compromised hub as a pivot point for attacking other devices within the local network. The remote exploitability aspect makes this particularly dangerous as it requires no physical access to the device, and the vulnerability can be triggered through standard web-based attack vectors.
Mitigation strategies for CVE-2018-3917 should focus on immediate firmware updates from Samsung, as the company likely released patches addressing the specific buffer overflow condition. Network segmentation and access control measures should be implemented to limit exposure of these devices to untrusted networks, while firewall rules can be configured to restrict HTTP access to the affected services. Input validation controls should be strengthened at the application level to prevent overly long parameter values from reaching the vulnerable code paths. Security monitoring should include detection of unusual HTTP request patterns that might indicate exploitation attempts, particularly those involving long "region" parameter values. The vulnerability highlights the importance of proper secure coding practices, specifically avoiding dangerous functions like strcpy in favor of safer alternatives such as strncpy or strlcpy that provide bounds checking. Organizations should also consider implementing network-based intrusion detection systems to monitor for exploitation attempts targeting this specific vulnerability, while conducting regular vulnerability assessments to identify similar issues in other IoT devices within their environments. Regular firmware updates and security patch management processes should be established to prevent similar vulnerabilities from being exploited in the future.