CVE-2017-16289 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_utc, at 0x9d0193ac, the value for the `offset` key is copied using `strcpy` to the buffer at `$sp+0x2d0`.This buffer is 100 bytes large, sending anything longer will cause a buffer overflow.
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Analysis
by VulDB Data Team • 02/04/2023
The vulnerability described in CVE-2017-16289 represents a critical stack-based buffer overflow in the Insteon Hub's PubNub message handler component. This flaw exists within the firmware version 1012 of the Insteon Hub device, which is a smart home automation system that relies on PubNub messaging for communication between the hub and remote clients. The vulnerability specifically targets the "cc" channel functionality, making it particularly dangerous as it could be exploited through the public PubNub service that the device uses for remote management and control operations. The attack vector requires an authenticated HTTP request, indicating that while the vulnerability may be remotely exploitable, it likely requires some form of valid credentials or session token to initiate the malicious payload.
The technical implementation of this vulnerability involves a classic buffer overflow scenario where the `strcpy` function is used to copy data from the `offset` key parameter into a buffer located at `$sp+0x2d0` on the stack. This buffer has a fixed size of 100 bytes, making it susceptible to overflow when input data exceeds this limit. The specific memory address 0x9d0193ac where the overflow occurs indicates that this is a well-defined stack location that can be manipulated through careful crafting of the input parameters. The use of `strcpy` without bounds checking creates an ideal condition for exploitation, as the function will continue copying bytes until it encounters a null terminator, regardless of the buffer's capacity. This type of vulnerability is classified as CWE-121 Stack-based Buffer Overflow, which is a fundamental weakness in memory management that has been consistently identified as one of the most dangerous classes of software vulnerabilities.
The operational impact of this vulnerability extends beyond simple denial of service, as stack-based buffer overflows can potentially be leveraged for arbitrary code execution, privilege escalation, or complete system compromise. In the context of an Insteon Hub, which serves as a central controller for home automation systems, successful exploitation could allow attackers to gain unauthorized control over connected smart home devices, potentially leading to privacy breaches, physical security risks, or even manipulation of critical home systems such as lighting, heating, or security alarms. The vulnerability's location within the PubNub message handler suggests that attackers could potentially exploit this through the cloud-based PubNub infrastructure, making the attack surface broader than typical local network exploits. This aligns with ATT&CK technique T1059.007 Command and Scripting Interpreter: PowerShell, as the overflow could potentially enable attackers to execute arbitrary commands on the device through the compromised message handling system.
Mitigation strategies for this vulnerability should include immediate firmware updates from Insteon to address the buffer overflow issue, proper input validation and bounds checking in the PubNub message handler implementation, and network segmentation to limit access to the hub's management interfaces. The use of defensive programming practices such as `strncpy` instead of `strcpy`, implementing proper input length checks, and employing stack canaries or other memory protection mechanisms would significantly reduce the exploitability of similar vulnerabilities. Additionally, network monitoring should be implemented to detect unusual PubNub traffic patterns that might indicate exploitation attempts, and access controls should be strengthened to ensure that only authorized users can send commands to the hub through the PubNub service. The vulnerability demonstrates the importance of secure coding practices in embedded systems and highlights the risks associated with using potentially unsafe string handling functions in network-facing components of IoT devices.