CVE-2019-1839 in Remote PHY Device Software
Summary
by MITRE
A vulnerability in Cisco Remote PHY Device Software could allow an authenticated, local attacker to execute commands on the underlying Linux shell of an affected device with root privileges. The vulnerability occurs because the affected software improperly sanitizes user-supplied input. An attacker who has valid administrator access to an affected device could exploit this vulnerability by supplying various CLI commands with crafted arguments. A successful exploit could allow the attacker to run arbitrary commands as the root user, allowing complete compromise of the system.
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Analysis
by VulDB Data Team • 11/28/2023
The vulnerability identified as CVE-2019-1839 represents a critical command injection flaw within Cisco Remote PHY Device Software that fundamentally undermines the security posture of affected network infrastructure. This weakness resides in the improper sanitization of user-supplied input within the device's command line interface, creating a pathway for authenticated attackers to escalate their privileges and execute arbitrary code with root-level permissions. The vulnerability specifically affects devices running Cisco Remote PHY Software versions prior to 1.0.11, making it particularly dangerous in enterprise environments where these devices often serve as critical components in wireless infrastructure deployments.
The technical exploitation of this vulnerability leverages the software's failure to properly validate and sanitize command line arguments passed through the CLI interface. When an authenticated administrator interacts with the device's command line, the system does not adequately filter or escape input parameters, allowing maliciously crafted arguments to bypass normal security controls. This design flaw aligns with CWE-77, which specifically addresses command injection vulnerabilities, and demonstrates how insufficient input validation can create pathways for privilege escalation attacks. The vulnerability operates at the kernel level through the underlying Linux shell, meaning that successful exploitation directly compromises the device's operating system rather than merely affecting application-level functionality.
From an operational perspective, the impact of CVE-2019-1839 extends far beyond simple unauthorized access, as it provides attackers with complete system compromise capabilities. An attacker with valid administrator credentials can leverage this vulnerability to execute arbitrary commands with root privileges, effectively granting them unrestricted control over the affected device. This level of access enables adversaries to modify system configurations, install backdoors, exfiltrate sensitive data, or use the compromised device as a launch point for further attacks within the network. The vulnerability's classification under ATT&CK technique T1059.004 (Command and Scripting Interpreter) highlights its potential for lateral movement and persistence within enterprise environments where these devices often form part of critical network infrastructure.
Organizations must implement immediate mitigations including upgrading to Cisco Remote PHY Software version 1.0.11 or later, which contains the necessary patches to address the input sanitization issues. Network segmentation and access control measures should be reinforced to limit administrator access to only necessary personnel, while monitoring solutions should be deployed to detect anomalous command execution patterns. The vulnerability's exploitation requires valid administrator credentials, making credential management and access control policies crucial defensive measures. Additionally, regular security assessments and vulnerability scanning should be conducted to identify potentially affected devices within the network infrastructure, as the impact of this vulnerability could extend to wireless access points, base stations, and other network components that rely on Cisco Remote PHY functionality.