CVE-2020-3161 in IP Phone
Summary
by MITRE
A vulnerability in the web server for Cisco IP Phones could allow an unauthenticated, remote attacker to execute code with root privileges or cause a reload of an affected IP phone, resulting in a denial of service (DoS) condition. The vulnerability is due to a lack of proper input validation of HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to the web server of a targeted device. A successful exploit could allow the attacker to remotely execute code with root privileges or cause a reload of an affected IP phone, resulting in a DoS condition.
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Analysis
by VulDB Data Team • 02/24/2025
The vulnerability identified as CVE-2020-3161 represents a critical security flaw in Cisco IP Phone web servers that exposes devices to remote code execution and denial of service attacks. This vulnerability specifically affects Cisco IP Phones running web server functionality, creating a pathway for unauthenticated attackers to gain unauthorized access to critical network infrastructure. The flaw stems from insufficient input validation mechanisms within the HTTP request processing pipeline of these devices, allowing malicious actors to craft specially designed requests that bypass normal security controls. The impact extends beyond simple network disruption as the vulnerability enables attackers to execute arbitrary code with root privileges, effectively compromising the entire device and potentially the broader network ecosystem.
The technical exploitation of this vulnerability occurs through the manipulation of HTTP requests sent to the affected web server components of Cisco IP Phones. When the web server receives a crafted HTTP request that contains malicious input, the lack of proper validation allows the device to process and execute unintended commands. This flaw aligns with CWE-20, which describes improper input validation as a fundamental weakness that enables various attack vectors including code execution and privilege escalation. The vulnerability's classification as a remote code execution flaw means that attackers do not require physical access or credentials to exploit the device, making it particularly dangerous in enterprise environments where IP phones serve as critical communication infrastructure. The attack surface is further expanded by the fact that these devices are often deployed in network perimeters where they may be accessible to external networks, creating additional exposure vectors.
The operational consequences of this vulnerability are severe and multifaceted, affecting both the availability and integrity of communication systems. Successful exploitation can result in complete device compromise, allowing attackers to execute commands as root user, modify device configurations, or establish persistent access points within the network. The potential for denial of service attacks through device reloads creates additional operational disruptions that can severely impact business continuity, particularly in environments where voice communication is critical for operations. Organizations may experience cascading effects as compromised IP phones can serve as entry points for broader network infiltration, potentially enabling lateral movement attacks that align with ATT&CK technique T1071.3 for application layer protocol usage. The vulnerability affects multiple Cisco IP Phone models and software versions, requiring comprehensive assessment and remediation across affected deployments.
Mitigation strategies for CVE-2020-3161 should prioritize immediate implementation of network segmentation and access control measures to limit exposure of IP phones to untrusted networks. Organizations should deploy firewalls and access control lists to restrict HTTP access to these devices, ensuring that only authorized management systems can communicate with the web server components. Cisco has released security advisories and software patches addressing this vulnerability, which should be applied immediately to all affected devices following vendor guidance and best practices for patch management. Network monitoring solutions should be enhanced to detect anomalous HTTP traffic patterns that may indicate exploitation attempts, while security teams should implement regular vulnerability assessments to identify similar input validation weaknesses in other network devices. The remediation process should also include comprehensive network audits to ensure that no other devices within the environment may be susceptible to similar vulnerabilities, particularly those running web server functionality with inadequate input validation controls.