CVE-2017-12305 in IP Phone 8800
Summary
by MITRE
A vulnerability in the debug interface of Cisco IP Phone 8800 series could allow an authenticated, local attacker to execute arbitrary commands, aka Debug Shell Command Injection. The vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by authenticating to the device and submitting additional command input to the affected parameter in the debug shell. Cisco Bug IDs: CSCvf80034.
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Analysis
by VulDB Data Team • 01/24/2021
The vulnerability identified as CVE-2017-12305 affects Cisco IP Phone 8800 series devices and represents a critical security flaw in the device's debug interface implementation. This vulnerability stems from inadequate input validation mechanisms within the debug shell functionality, creating a pathway for authenticated local attackers to execute arbitrary commands on the affected system. The issue manifests through the debug interface where legitimate authentication credentials can be leveraged to submit malicious command inputs that bypass normal security controls and execute with the privileges of the authenticated user. The vulnerability specifically impacts the debug shell functionality of these IP phones, which are commonly deployed in enterprise environments for voice communication services. The affected devices operate under the assumption that authenticated users can be trusted, creating a dangerous trust model that allows privilege escalation through command injection techniques.
The technical exploitation of this vulnerability follows a command injection pattern that aligns with CWE-77 and CWE-94, where insufficient input validation allows attackers to inject malicious commands into the debug shell interface. When an authenticated user accesses the debug shell, the system fails to properly sanitize input parameters, enabling attackers to append additional commands that get executed in the context of the debug interface. This creates a scenario where legitimate administrative functions become vectors for unauthorized code execution, as the debug shell operates with elevated privileges and lacks proper command filtering mechanisms. The vulnerability exists because the debug interface does not adequately validate or sanitize command inputs, allowing attackers to manipulate the execution flow of the debug shell and potentially gain deeper system access. The exploitation requires local authentication access to the device, making it particularly dangerous in environments where physical access or administrative credentials might be compromised.
The operational impact of this vulnerability extends beyond simple command execution, as it provides attackers with potential access to sensitive system functions and data within the IP phone environment. An attacker who successfully exploits this vulnerability could potentially access call logs, configuration files, network settings, and other sensitive information stored on the device. The debug shell typically provides access to underlying system components that may not be available through normal user interfaces, making this a particularly attractive target for attackers seeking to escalate privileges or extract information from enterprise voice systems. The vulnerability affects the integrity and confidentiality of the communication infrastructure, as the compromised devices could serve as entry points for broader network attacks or as persistent backdoors within the enterprise environment. Additionally, the impact extends to availability as attackers could potentially disrupt phone services or modify device configurations to cause service degradation.
Organizations should implement immediate mitigations including disabling unused debug interfaces, enforcing strict access controls for authentication mechanisms, and implementing network segmentation to limit access to these devices. Regular security assessments should verify that debug interfaces are properly secured and that authentication controls are robust against credential compromise. Cisco recommends applying the latest security patches and firmware updates that address the input validation issues within the debug shell implementation. Network monitoring should be enhanced to detect unusual command execution patterns that might indicate exploitation attempts. The vulnerability highlights the importance of principle of least privilege and proper input sanitization in embedded systems, particularly those with debug interfaces that may be accessible to authenticated users. Security teams should also consider implementing device access logging and anomaly detection to identify potential exploitation attempts. This vulnerability serves as a reminder of the critical need for secure coding practices in embedded systems and the importance of validating all user inputs regardless of authentication status. The issue also aligns with ATT&CK technique T1059 which covers command and scripting interpreters, demonstrating how insecure debug interfaces can be leveraged for persistent access and privilege escalation within enterprise environments.