CVE-2020-3176 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 exists because the affected software does not properly sanitize user-supplied input. An attacker who has valid administrator access to an affected device could exploit this vulnerability by supplying certain CLI commands with crafted arguments. A successful exploit could allow the attacker to run arbitrary commands as the root user, which could result in a complete system compromise.
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Analysis
by VulDB Data Team • 04/09/2024
The vulnerability identified as CVE-2020-3176 represents a critical command injection flaw in Cisco Remote PHY Device Software that fundamentally undermines the security posture of affected network infrastructure. This vulnerability operates at the intersection of improper input validation and privilege escalation, creating a pathway for authenticated attackers to gain root-level access to the underlying Linux operating system. The flaw manifests specifically within the command line interface processing mechanisms where user-supplied input fails to undergo proper sanitization before being executed by the system shell. This represents a classic example of a command injection vulnerability that directly violates security best practices and industry standards such as CWE-77, which categorizes improper input sanitization leading to command execution. The vulnerability is particularly concerning because it requires only valid administrator credentials to exploit, meaning that attackers who have already gained administrative access can leverage this weakness to escalate their privileges to the highest possible level within the system.
The technical exploitation of CVE-2020-3176 involves an attacker crafting specific CLI commands with maliciously formatted arguments that bypass input validation checks implemented by the software. When these crafted inputs are processed by the vulnerable software, they are passed directly to the underlying Linux shell without proper sanitization, allowing arbitrary command execution. This type of vulnerability aligns with ATT&CK technique T1059.001, which describes command and scripting interpreter usage, specifically targeting the Linux shell environment. The root cause stems from the software's failure to properly validate and sanitize user input before executing commands, creating a direct path for attackers to manipulate the system's execution flow. The vulnerability essentially allows an attacker to execute any command that the root user could execute, potentially enabling complete system compromise, data exfiltration, or persistent backdoor installation.
The operational impact of this vulnerability extends far beyond simple privilege escalation, as it provides attackers with complete control over the affected device's underlying operating system. Once exploited, the attacker gains the ability to modify system files, install malicious software, create new user accounts, and potentially use the compromised device as a pivot point for attacking other systems within the network. The vulnerability's exploitation capability directly maps to ATT&CK tactic TA0003, which encompasses privilege escalation, and technique T1566, related to credential harvesting and manipulation. Organizations running affected Cisco Remote PHY devices face significant risk of unauthorized access and potential network compromise, as these devices often serve critical roles in network infrastructure and may be located in sensitive operational environments. The vulnerability essentially transforms a device that should only allow administrative commands into a potential entry point for broader network infiltration and persistent access.
Mitigation strategies for CVE-2020-3176 should prioritize immediate software updates and patches provided by Cisco to address the input sanitization deficiencies. Organizations must implement strict access controls and monitoring for administrative sessions to detect potential exploitation attempts. Network segmentation and principle of least privilege should be enforced to limit the potential impact if exploitation occurs. The vulnerability's remediation directly aligns with security controls recommended in NIST SP 800-53 and ISO 27001 frameworks, particularly those addressing input validation and access control. Additionally, implementing behavioral monitoring and anomaly detection systems can help identify suspicious command execution patterns that may indicate exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify similar input validation weaknesses in other network devices and applications, as this represents a common class of vulnerability that affects numerous network infrastructure components. The exploitation of such vulnerabilities often follows patterns identified in the MITRE ATT&CK framework, making proactive monitoring and response capabilities essential for organizations to prevent successful exploitation.