CVE-2024-44540 in AirMax
Summary
by MITRE • 09/23/2024
Ubiquiti AirMax firmware version firmware version 8 allows attackers with physical access to gain a privileged command shell via the UART Debugging Port.
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Analysis
by VulDB Data Team • 09/24/2024
The vulnerability identified as CVE-2024-44540 affects Ubiquiti AirMax firmware version 8 and represents a critical security flaw that undermines the physical security posture of network infrastructure devices. This vulnerability specifically targets the UART Debugging Port, which serves as a low-level communication interface typically reserved for manufacturing and diagnostic purposes. The flaw allows unauthorized individuals with physical access to gain elevated privileges and execute commands with root-level access to the device's operating system. This represents a significant escalation from standard user-level access to full administrative control, fundamentally compromising the device's security model and potentially enabling broader network compromise.
The technical implementation of this vulnerability stems from insufficient access controls and authentication mechanisms within the UART debugging interface. The UART port, when enabled, should typically require specific authorization or be completely disabled in production environments. However, in the affected firmware version, the debugging port remains accessible without proper authentication mechanisms, allowing any individual with physical access to connect to the serial console and obtain a privileged command shell. This design flaw aligns with CWE-284, which addresses improper access control, and specifically demonstrates weak privilege management in embedded systems. The vulnerability exists because the firmware fails to properly enforce access restrictions on the serial communication interface, creating an attack vector that bypasses normal security boundaries.
The operational impact of this vulnerability extends beyond individual device compromise to potentially affect entire network infrastructures. When attackers gain root access through the UART debugging port, they can modify firmware, extract sensitive configuration data, install backdoors, or manipulate network traffic routing. This capability enables persistent access to network segments and can facilitate lateral movement throughout the organization's infrastructure. The vulnerability's exploitation requires only physical access, making it particularly concerning for network equipment deployed in publicly accessible locations or areas where unauthorized physical access cannot be adequately controlled. According to ATT&CK framework, this vulnerability maps to T1059.004 (Command and Scripting Interpreter: Unix Shell) and T1068 (Exploitation for Privilege Escalation), highlighting the threat actor's ability to execute commands with elevated privileges and leverage the compromised device as a foothold for further network infiltration.
Organizations should implement immediate mitigations to address this vulnerability by disabling the UART debugging port in production environments or ensuring physical access controls are strictly enforced. The recommended approach involves configuring the device firmware to disable serial debugging interfaces when not actively required for maintenance operations. Network administrators should also conduct comprehensive inventory audits to identify all affected devices and implement proper physical security measures around network equipment. Additionally, regular firmware updates should be prioritized to ensure devices are running the latest security patches that address this specific vulnerability. Security monitoring should include detection of unauthorized serial connections and anomalous command execution patterns that might indicate exploitation attempts. The mitigation strategy should align with industry best practices for embedded system security and align with NIST SP 800-82 guidelines for industrial control systems security, emphasizing the importance of securing physical access points and implementing robust access control measures for all device interfaces.