CVE-2019-9121 in Motorola
Summary
by MITRE
An issue was discovered on Motorola C1 and M2 devices with firmware 1.01 and 1.07 respectively. This issue is a Command Injection allowing a remote attacker to execute arbitrary code, and get a root shell. A command Injection vulnerability allows attackers to execute arbitrary OS commands via a crafted /HNAP1 POST request. This occurs when any HNAP API function triggers a call to the system function with untrusted input from the request body for the SetSmartQoSSettings API function, as demonstrated by shell metacharacters in the smartqos_priority_devices field.
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Analysis
by VulDB Data Team • 07/29/2023
This vulnerability exists in Motorola C1 and M2 devices running firmware versions 1.01 and 1.07 respectively, representing a critical command injection flaw that enables remote code execution with root privileges. The vulnerability stems from improper input validation within the HNAP (Home Network Administration Protocol) implementation, specifically affecting the SetSmartQoSSettings API function. Attackers can exploit this weakness by crafting malicious /HNAP1 POST requests that contain shell metacharacters in the smartqos_priority_devices field, which then get processed through the system function without adequate sanitization. This represents a classic command injection vulnerability that falls under CWE-77, where untrusted data is directly incorporated into system commands without proper escaping or validation mechanisms.
The operational impact of this vulnerability is severe as it provides attackers with complete system compromise and root shell access to affected devices. Once exploited, attackers can execute arbitrary commands with the highest possible privileges, potentially leading to full network infiltration, data exfiltration, or use of the compromised device as a pivot point for further attacks. The remote nature of this vulnerability means that attackers do not require physical access or local network presence to exploit it, making it particularly dangerous for IoT and networking equipment. This vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, specifically shell commands, and represents a critical entry point for lateral movement within networks where these devices are deployed.
The technical exploitation occurs through the HNAP protocol's handling of the SetSmartQoSSettings API function, where the smartqos_priority_devices parameter is directly passed to system commands without proper input sanitization. This allows attackers to inject shell metacharacters such as semicolons, pipes, or other command separators that cause the system to execute unintended commands. The vulnerability demonstrates poor input validation practices and inadequate security controls in embedded device firmware implementations. Organizations should implement network segmentation to limit exposure, deploy intrusion detection systems to monitor for suspicious HNAP traffic patterns, and ensure timely firmware updates are applied to address this vulnerability. Additionally, network administrators should consider disabling unnecessary services and APIs, particularly those that accept user input without proper validation, as recommended by NIST SP 800-125 for embedded system security hardening.
The broader implications extend beyond individual device compromise to potential supply chain risks, as these devices may be deployed in enterprise environments where they serve as network infrastructure components. The vulnerability highlights the critical importance of input validation in network protocols and the necessity of applying security principles such as least privilege and defense in depth. Organizations should conduct comprehensive vulnerability assessments of their embedded device inventories, particularly focusing on network services that handle external input. The attack surface expansion through this vulnerability could enable more sophisticated attacks including persistent backdoor installation, network reconnaissance, and privilege escalation across multiple network segments. This vulnerability serves as a reminder of the critical security requirements for IoT device manufacturers and the need for comprehensive security testing throughout the development lifecycle, as outlined in ISO/IEC 27030 standards for security testing and validation.