CVE-2017-9389 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 allows a user to install applications written in the Lua programming language. Also the interface allows any user to write his/her application in the Lua language. However, this functionality is not protected by authentication and this allows an attacker to run arbitrary Lua code on the device. The POST request is forwarded to LuaUPNP daemon on the device. This binary handles the received Lua code in the function "LU::JobHandler_LuaUPnP::RunLua(LU::JobHandler_LuaUPnP *__hidden this, LU::UPnPActionWrapper *)". The value in the "code" parameter is then passed to the function "LU::LuaInterface::RunCode(char const*)" which actually loads the Lua engine and runs the code.
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Analysis
by VulDB Data Team • 10/05/2023
The vulnerability identified as CVE-2017-9389 affects VeraEdge 1.7.19 and Veralite 1.7.481 devices, representing a critical security flaw in home automation systems that enables arbitrary code execution. This issue stems from inadequate authentication controls within the device's web user interface, which provides functionality for users to develop and install applications written in the Lua programming language. The flaw exists because the system allows any user to execute Lua code without proper authentication mechanisms, creating an exploitable entry point for malicious actors. The vulnerability specifically impacts the device's LuaUPNP daemon, which processes POST requests containing Lua code through a designated web interface.
The technical exploitation occurs when an attacker submits a POST request containing malicious Lua code to the device's web interface, which is then forwarded to the LuaUPNP daemon. The daemon processes this request through the function "LU::JobHandler_LuaUPnP::RunLua" which accepts the code parameter and passes it to "LU::LuaInterface::RunCode" function. This function initializes the Lua engine and executes the provided code with the privileges of the web server process. The lack of authentication verification means that any remote attacker can submit arbitrary Lua code without requiring valid credentials, effectively granting them complete control over the device's execution environment. This represents a classic privilege escalation vulnerability where unauthenticated access leads to arbitrary code execution.
The operational impact of this vulnerability is severe as it allows attackers to gain complete control over affected Vera devices, potentially leading to unauthorized access to home networks, data exfiltration, or further lateral movement within the network infrastructure. The vulnerability creates a persistent backdoor that can be used to maintain access to the device, execute malicious scripts, and potentially compromise other connected IoT devices. Given that these devices typically operate in residential environments, the attack surface extends to personal data, home automation controls, and network access. The vulnerability affects the device's core functionality by undermining the fundamental security assumptions of the web interface, which should have enforced proper authentication before allowing code execution capabilities.
Mitigation strategies for CVE-2017-9389 should focus on implementing proper authentication controls and access restrictions to prevent unauthorized code execution. Organizations should immediately update affected devices to the latest firmware versions provided by Vera, as vendors typically release patches addressing such vulnerabilities. Network segmentation and firewall rules should be implemented to restrict access to the device's web interface, particularly from untrusted networks. The vulnerability aligns with CWE-284 (Improper Access Control) and maps to ATT&CK technique T1059.007 (Command and Scripting Interpreter: Lua) in the MITRE ATT&CK framework, highlighting the need for input validation and authentication controls. Additionally, security monitoring should be enhanced to detect suspicious POST requests containing unexpected Lua code patterns, and regular security assessments should be conducted to identify similar authentication bypass vulnerabilities in IoT device management interfaces.