CVE-2017-16296 in Insteon
Summary
by MITRE • 01/12/2023
Multiple exploitable buffer overflow vulnerabilities exist in the PubNub message handler for the "cc" channel of Insteon Hub running firmware version 1012. Specially crafted commands sent through the PubNub service can cause a stack-based buffer overflow overwriting arbitrary data. An attacker should send an authenticated HTTP request to trigger this vulnerability. In cmd s_schd, at 0x9d01a1d4, the value for the `days` key is copied using `strcpy` to the buffer at `$sp+0x2b0`.This buffer is 32 bytes large, sending anything longer will cause a buffer overflow.
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Analysis
by VulDB Data Team • 02/04/2023
The vulnerability described in CVE-2017-16296 represents a critical stack-based buffer overflow in the Insteon Hub's PubNub message handler component. This flaw exists within the firmware version 1012 of the Insteon Hub device, which is a smart home automation system that relies on PubNub messaging for communication between devices and the central hub. The vulnerability specifically targets the "cc" channel functionality, which is part of the hub's scheduling and command processing mechanisms. The issue stems from improper input validation and unsafe string handling practices that allow malicious actors to manipulate the system through specially crafted commands transmitted via the PubNub service infrastructure.
The technical implementation of this vulnerability occurs within the cmd s_schd function at memory address 0x9d01a1d4 where the system processes the `days` key value from incoming PubNub messages. The flaw manifests when the system employs the unsafe `strcpy` function to copy data from the incoming message into a buffer located at `$sp+0x2b0` on the stack. This buffer has a fixed size of only 32 bytes, making it extremely susceptible to overflow when the input data exceeds this limit. The use of `strcpy` without proper bounds checking creates a classic stack buffer overflow condition where excessive input data overwrites adjacent memory locations, potentially including return addresses, saved registers, and other critical program state information. This vulnerability is categorized under CWE-121 as a stack-based buffer overflow, which is a well-known weakness that has been extensively documented in cybersecurity literature and represents one of the most common attack vectors for privilege escalation and arbitrary code execution.
The operational impact of this vulnerability is severe as it provides attackers with a pathway to compromise the Insteon Hub device and potentially gain unauthorized access to the entire smart home network it controls. The requirement for an authenticated HTTP request to trigger this vulnerability means that attackers would need to either obtain valid credentials or exploit another vulnerability to gain access to the system's authentication mechanisms. Once exploited, the buffer overflow could allow attackers to execute arbitrary code on the device, potentially enabling them to modify scheduling configurations, access sensitive user data, or use the compromised hub as a pivot point to attack other devices on the same network. The attack surface is particularly concerning because smart home hubs often serve as central control points for multiple connected devices, making them attractive targets for cybercriminals seeking to establish persistent access to residential or commercial environments. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation, demonstrating how buffer overflows can be leveraged for broader system compromise.
Mitigation strategies for this vulnerability should focus on immediate firmware updates from the vendor to address the unsafe string handling practices and implement proper input validation. System administrators should ensure that the Insteon Hub firmware is updated to the latest version that contains patches for this specific buffer overflow issue. Additionally, network segmentation should be implemented to isolate the hub from critical network segments, and access controls should be strengthened to prevent unauthorized HTTP requests to the device. The implementation of input sanitization measures including bounds checking, use of safer string functions like `strncpy` instead of `strcpy`, and proper validation of all incoming PubNub message parameters would prevent similar vulnerabilities from occurring in the future. Network monitoring should also be enhanced to detect anomalous patterns in PubNub message traffic that might indicate exploitation attempts. Security assessments should include thorough code reviews focusing on buffer management and string handling practices to identify and remediate similar weaknesses in other components of the system. The vulnerability demonstrates the importance of following secure coding practices and adhering to industry standards such as those outlined in the CERT/CC secure coding guidelines and OWASP secure coding practices to prevent buffer overflow exploits in embedded systems and IoT devices.