CVE-2017-9388 in VeraEdge
Summary
by MITRE
An issue was discovered on Vera VeraEdge 1.7.19 and Veralite 1.7.481 devices. The device provides a web user interface that allows a user to manage the device. As a part of the functionality the device firmware file contains a file known as proxy.sh which allows the device to proxy a specific request to and from from another website. This is primarily used as a method of communication between the device and Vera website when the user is logged in to the https://home.getvera.com and allows the device to communicate between the device and website. One of the parameters retrieved by this specific script is "url". This parameter is not sanitized by the script correctly and is passed in a call to "eval" to execute "curl" functionality. This allows an attacker to escape from the executed command and then execute any commands of his/her choice.
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Analysis
by VulDB Data Team • 10/05/2023
The vulnerability identified in CVE-2017-9388 represents a critical command injection flaw affecting VeraEdge 1.7.19 and Veralite 1.7.481 devices, fundamentally compromising the security posture of these home automation systems. This issue resides within the proxy.sh script that serves as a communication bridge between the device and Vera's cloud infrastructure at https://home.getvera.com. The device's web interface functionality relies on this script to proxy requests, enabling seamless integration with the Vera ecosystem. However, the implementation contains a dangerous flaw where user-controllable input is directly processed without proper sanitization before being executed within an eval statement.
The technical exploitation occurs through the unvalidated "url" parameter that flows into the curl execution via eval, creating a classic command injection vulnerability. This flaw directly maps to CWE-77 and CWE-94, representing improper input validation and execution of code from external sources. The vulnerability allows attackers to manipulate the curl command execution by injecting malicious payloads through the url parameter, effectively bypassing the intended proxy functionality and gaining arbitrary command execution capabilities on the device. This represents a severe privilege escalation vector since the device processes these commands with elevated privileges typically associated with system-level operations.
The operational impact of this vulnerability extends beyond simple command execution, as it provides attackers with complete control over the affected devices, potentially enabling them to modify device configurations, access sensitive user data, or establish persistent backdoors. The attack surface is particularly concerning given that these are home automation devices that often operate in trusted network environments, making them ideal targets for lateral movement within home networks. From an attack framework perspective, this vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter and T1071.004 for application layer protocol, as it enables attackers to leverage the device's legitimate communication channels to execute malicious commands.
Mitigation strategies should focus on immediate firmware updates from Vera to address the root cause of the unsanitized input processing. Network segmentation and firewall rules can help limit exposure by restricting access to the device's web interface from untrusted networks. Additionally, implementing input validation measures that sanitize all user-provided parameters before processing, particularly those destined for eval functions, would prevent similar vulnerabilities from occurring in the future. Security monitoring should include detection of unusual command execution patterns on the device, as well as network traffic analysis for anomalous proxy requests that might indicate exploitation attempts. Organizations should also consider implementing zero-trust network principles for IoT devices, ensuring that even within trusted networks, devices maintain proper authentication and authorization controls to prevent unauthorized access and command execution.