CVE-2019-15312 in Zolo Halo
Summary
by MITRE
An issue was discovered on Zolo Halo devices via the Linkplay firmware. There is a Zolo Halo DNS rebinding attack. The device was found to be vulnerable to DNS rebinding. Combined with one of the many /httpapi.asp endpoint command-execution security issues, the DNS rebinding attack could allow an attacker to compromise the victim device from the Internet.
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Analysis
by VulDB Data Team • 07/02/2020
The vulnerability identified as CVE-2019-15312 represents a critical security flaw in Zolo Halo devices running Linkplay firmware, specifically exposing these devices to DNS rebinding attacks that can be leveraged for remote code execution. This issue stems from the device's improper handling of DNS responses during network communication, creating a pathway for attackers to bypass network security controls and gain unauthorized access to the device. The vulnerability is particularly concerning because it allows remote attackers to manipulate the device's network behavior through DNS resolution manipulation, effectively enabling them to redirect traffic intended for legitimate services to attacker-controlled endpoints.
The technical implementation of this vulnerability involves the device's failure to properly validate DNS responses and maintain consistent network state during the resolution process. When a device receives DNS responses, it should validate that the responses correspond to expected network contexts and maintain proper security boundaries. In the case of Zolo Halo devices, attackers can exploit this by crafting malicious DNS responses that initially point to legitimate internal services but then redirect to attacker-controlled external endpoints. This allows the attacker to establish a connection to the device's internal services from an external network location, effectively bypassing the device's intended network isolation. The flaw aligns with CWE-611, which addresses Improper Restriction of XML External Entity Reference, and represents a variant of DNS rebinding attacks that manipulate domain name resolution to gain unauthorized access to network resources.
The operational impact of this vulnerability extends beyond simple network access manipulation, as it combines with existing command execution vulnerabilities present in the /httpapi.asp endpoint to create a complete remote exploitation chain. This combination allows attackers to not only gain initial access but also to execute arbitrary commands on the compromised device, potentially leading to full system compromise. The attack surface is particularly broad because the vulnerability affects devices that are accessible from the internet, making them vulnerable to exploitation by attackers who may be located anywhere in the world. The integration of DNS rebinding with command execution capabilities creates a sophisticated attack vector that can be used to establish persistent access to the device, potentially allowing for data exfiltration, system modification, or use as a pivot point for attacks on other network resources.
Mitigation strategies for this vulnerability require immediate implementation of network-level protections and firmware updates to address the underlying DNS handling issues. Organizations should implement DNS filtering mechanisms that prevent external DNS responses from being accepted for internal device communication, and consider network segmentation to isolate affected devices from critical network segments. The recommended approach involves deploying DNS servers that can properly validate and restrict DNS responses, implementing proper access controls for the httpapi.asp endpoint, and ensuring that all devices are running updated firmware versions that address the specific DNS rebinding vulnerabilities. Security controls should also include monitoring for unusual DNS resolution patterns and implementing network access controls that restrict communication to trusted endpoints. This vulnerability demonstrates the importance of proper network boundary enforcement and highlights the need for comprehensive security testing of network device firmware to identify and remediate similar issues that may exist in other network infrastructure components. The attack vector represents a clear violation of the principle of least privilege and demonstrates how DNS-related vulnerabilities can be leveraged to create persistent access to network devices that should remain isolated from external threats.