CVE-2018-17563 in GXP16xx VoIP
Summary
by MITRE
A Malformed Input String to /cgi-bin/api-get_line_status on Grandstream GXP16xx VoIP 1.0.4.128 phones allows attackers to dump the device's configuration in cleartext.
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Analysis
by VulDB Data Team • 08/21/2023
The vulnerability identified as CVE-2018-17563 affects Grandstream GXP16xx VoIP phones running firmware version 1.0.4.128 and potentially other affected models. This represents a critical security flaw in the device's web-based administration interface that exposes sensitive configuration data through a poorly validated input parameter. The vulnerability resides in the /cgi-bin/api-get_line_status endpoint which processes input strings without adequate sanitization or validation mechanisms.
The technical flaw manifests when an attacker submits a malformed input string to the api-get_line_status CGI endpoint. This input validation failure creates a path where arbitrary data can be passed through the system's parsing logic, ultimately leading to the exposure of the device's complete configuration in cleartext format. The vulnerability stems from insufficient input validation and sanitization practices, allowing attackers to manipulate the application's expected input format and trigger unintended behavior.
The operational impact of this vulnerability is severe as it provides attackers with complete access to sensitive telephony configuration data. The cleartext exposure includes credentials, SIP registration details, network configuration parameters, and potentially other sensitive information that could be used for further attacks within the network. This configuration dump enables attackers to establish persistent access to the VoIP infrastructure and potentially escalate privileges or conduct man-in-the-middle attacks against voice communications. The vulnerability affects organizations relying on these devices for voice services and exposes them to significant risk of unauthorized access and data compromise.
This vulnerability aligns with CWE-20, which describes improper input validation, and represents a classic example of how insufficient validation can lead to information disclosure. From an attack perspective, this weakness maps to multiple ATT&CK techniques including credential access through information discovery and privilege escalation via configuration data manipulation. The vulnerability also demonstrates poor secure coding practices related to input sanitization and output encoding that should be addressed through comprehensive security testing and code review processes. Organizations should implement immediate mitigations including firmware updates, network segmentation, and access control measures to prevent exploitation while planning for comprehensive security assessments of their VoIP infrastructure.
The vulnerability highlights the importance of proper input validation in web applications and the critical need for secure coding practices in embedded systems. It demonstrates how even seemingly minor input validation flaws can result in complete system compromise, particularly in network infrastructure devices where configuration data often contains sensitive authentication credentials and operational parameters. This issue underscores the necessity for regular security assessments and timely firmware updates to protect against known vulnerabilities in network equipment.