CVE-2017-16336 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_event_var, at 0x9d01eeb0, the value for the `s_value` key is copied using `strcpy` to the buffer at `$sp+0x10`.This buffer is 244 bytes large, sending anything longer will cause a buffer overflow.
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Analysis
by VulDB Data Team • 02/04/2023
The vulnerability identified as CVE-2017-16336 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 hub that communicates with various IoT devices through the PubNub messaging service. The vulnerability specifically targets the "cc" channel within the PubNub handler, creating an exploitable condition that allows remote code execution through carefully crafted malicious payloads. The technical implementation of this vulnerability stems from improper input validation and unsafe string handling practices within the device's firmware codebase.
The core technical flaw manifests in the cmd s_event_var function at memory address 0x9d01eeb0 where the application processes the `s_value` key from incoming PubNub messages. The implementation uses the dangerous `strcpy` function to copy data from the incoming message into a buffer located at stack pointer offset $sp+0x10. This buffer has a fixed size of 244 bytes, making it susceptible to overflow when malicious input exceeds this limit. The use of `strcpy` without bounds checking creates a classic buffer overflow condition where attacker-controlled data can overwrite adjacent stack memory, potentially corrupting program execution flow and allowing arbitrary code execution. This vulnerability directly maps to CWE-121, which describes stack-based buffer overflow conditions, and aligns with ATT&CK technique T1059.007 for command and scripting interpreter.
The operational impact of this vulnerability extends beyond simple privilege escalation as it enables full remote code execution on the Insteon Hub device, effectively giving attackers complete control over the smart home automation system. An attacker needs to send an authenticated HTTP request to trigger this vulnerability, which means they must first obtain valid credentials for the device or exploit another authentication bypass mechanism. Once exploited, the attacker can gain persistent access to the network, potentially using the device as a foothold for further attacks within the home network. The vulnerability affects the device's ability to process legitimate PubNub messages, creating both a security compromise and potential denial-of-service condition. This represents a significant risk for users who rely on smart home automation systems for security and convenience, as the compromise of such devices could lead to unauthorized access to connected home security systems, lighting controls, and other critical infrastructure.
The exploitation of this vulnerability requires careful crafting of payloads that exceed the 244-byte buffer limit while maintaining proper message structure to avoid detection. The stack-based nature of the overflow allows for precise memory corruption that can be leveraged to overwrite return addresses, function pointers, or other critical program state information. Security researchers should note that this vulnerability demonstrates poor software development practices in embedded IoT devices, where memory safety checks are often omitted due to resource constraints or development oversight. Organizations should implement immediate mitigations including firmware updates, network segmentation, and monitoring for unusual PubNub traffic patterns. The vulnerability also highlights the importance of secure coding practices in IoT devices and the need for proper input validation and bounds checking even in resource-constrained environments. Network administrators should consider implementing firewall rules to restrict access to the PubNub service endpoints and monitor for anomalous traffic patterns that might indicate exploitation attempts.