CVE-2017-16327 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_init_event, at 0x9d01ea88, the value for the `s_event_offset` 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 identified as CVE-2017-16327 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 serves as a smart home automation gateway connecting various IoT devices through the PubNub messaging service. The vulnerability specifically targets the "cc" channel functionality, making it particularly concerning for users who rely on PubNub-based communication for their home automation systems. The issue stems from improper input validation and unsafe string handling practices within the device's firmware code.
The technical implementation of this vulnerability occurs within the cmd s_init_event function at memory address 0x9d01ea88 where the value associated with the `s_event_offset` key is copied using the dangerous strcpy function. This function does not perform bounds checking, allowing an attacker to write data beyond the allocated buffer boundaries. The vulnerable buffer is positioned at $sp+0x2b0 with a fixed size of only 32 bytes, making it extremely susceptible to overflow attacks. When an attacker sends a malicious payload exceeding this 32-byte limit, the excess data overwrites adjacent stack memory locations, potentially corrupting program execution flow and enabling arbitrary code execution.
The operational impact of this vulnerability extends beyond simple buffer corruption, as it provides attackers with a pathway for remote code execution on the Insteon Hub device. Since the vulnerability requires an authenticated HTTP request to trigger, attackers must first obtain valid credentials or exploit another vulnerability to gain access to the device's administrative interface. This authentication requirement does not mitigate the severity of the flaw, as it still allows for complete system compromise once access is obtained. The vulnerability creates a persistent backdoor that could enable attackers to monitor network traffic, manipulate connected smart home devices, or use the device as a pivot point for attacking other systems within the local network. This aligns with CWE-121 Stack-based Buffer Overflow, which specifically addresses buffer overflows occurring in stack memory regions where data can overwrite adjacent memory locations.
The exploitation of this vulnerability demonstrates a classic attack pattern that would fall under the MITRE ATT&CK framework's T1059.007 technique for Command and Scripting Interpreter, as successful exploitation would allow attackers to execute arbitrary commands on the compromised device. Additionally, the vulnerability's nature as a privilege escalation vector could enable attackers to achieve T1068 Privilege Escalation through the exploitation of the buffer overflow. The Insteon Hub's role as a central automation controller makes this vulnerability particularly dangerous, as it could allow attackers to gain unauthorized access to an entire smart home ecosystem. The device's network connectivity and integration with various IoT protocols create multiple attack surfaces that could be leveraged by threat actors.
Mitigation strategies for this vulnerability should include immediate firmware updates from Insteon to address the buffer overflow issue and implement network segmentation to limit access to the device. Network monitoring should be enhanced to detect unusual PubNub traffic patterns and unauthorized HTTP requests. Access controls must be strengthened through the implementation of multi-factor authentication and regular credential rotation. The vulnerability highlights the importance of secure coding practices, specifically avoiding dangerous functions like strcpy in favor of safer alternatives such as strncpy or strlcpy. Organizations should also implement regular security assessments of IoT devices and establish incident response procedures for dealing with compromised smart home infrastructure. The vulnerability serves as a reminder of the critical need for proper input validation and memory management in embedded systems, particularly those handling network communications and user data.