CVE-2017-9384 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 relay.sh which allows the device to create relay ports and connect the device to Vera servers. This is primarily used as a method of communication between the device and Vera servers so the devices can be communicated with even when the user is not at home. One of the parameters retrieved by this specific script is "remote_host". This parameter is not sanitized by the script correctly and is passed in a call to "eval" to execute another script where remote_host is concatenated to be passed a parameter to the second script. 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 as CVE-2017-9384 affects VeraEdge 1.7.19 and Veralite 1.7.481 devices, representing a critical command injection flaw within the device's web management interface. This issue stems from improper input validation in the relay.sh script that handles communication between the device and Vera servers, creating a dangerous execution path for malicious actors. The vulnerability operates through a specific parameter named "remote_host" that is processed without adequate sanitization, allowing attackers to manipulate the command execution flow. The script's design incorporates the unsanitized parameter directly into an eval function call, which serves as the primary attack vector for this command injection exploit. This architectural flaw enables remote attackers to execute arbitrary commands on the affected devices, fundamentally compromising the system's security posture.
The technical implementation of this vulnerability aligns with CWE-77 and CWE-94, which respectively address improper neutralization of special elements used in a command and execution of code based on a control structure. The attack mechanism exploits the eval function's dangerous nature by concatenating attacker-controlled input directly into the command execution pipeline, bypassing normal input validation mechanisms. The relay.sh script's handling of the "remote_host" parameter demonstrates poor security practices where user-supplied data flows directly into system command execution without proper sanitization or escaping. This vulnerability operates at the application layer and can be exploited through the web interface, requiring no privileged access or authentication to initiate the attack. The flaw represents a classic example of unsafe command construction where dynamic input is directly embedded into shell commands without proper escaping or validation.
The operational impact of CVE-2017-9384 extends beyond simple command execution, potentially enabling full system compromise and persistent access to affected Vera devices. Attackers can leverage this vulnerability to gain unauthorized control over the device's functionality, potentially accessing network resources, modifying device configurations, or establishing backdoors for continued access. The compromised device becomes a potential pivot point for attacking other systems within the local network, as the Vera devices often serve as central hubs for home automation and security systems. This vulnerability directly maps to ATT&CK technique T1059.001, which covers command and scripting interpreter execution, and T1068, which addresses local privilege escalation. The exposure of the device to remote command execution creates a significant risk for home network security, particularly given that these devices are often deployed in unsecured environments without proper network segmentation.
Mitigation strategies for this vulnerability should focus on immediate firmware updates from Vera to address the command injection flaw in relay.sh. Network administrators should implement strict access controls and firewall rules to limit access to the device's web interface, particularly from untrusted networks. The implementation of input validation and output encoding mechanisms within the device's firmware would prevent similar issues in future deployments. Security monitoring should include detection of unusual command execution patterns and unauthorized access attempts to the device's web interface. Organizations should also consider network segmentation to isolate these devices from critical systems and implement intrusion detection systems to monitor for exploitation attempts. The vulnerability highlights the importance of secure coding practices, particularly in embedded systems where command execution functions are commonly used for device management purposes. Regular security assessments and penetration testing of home automation devices can help identify similar vulnerabilities before they can be exploited by malicious actors.