CVE-2019-1010200 in Voice Builder
Summary
by MITRE
Voice Builder Prior to commit c145d4604df67e6fc625992412eef0bf9a85e26b and f6660e6d8f0d1d931359d591dbdec580fef36d36 is affected by: CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection'). The impact is: Remote code execution with the same privileges as the servers. The component is: Two web servers in the projects expose three vulnerable endpoints that can be accessed remotely. The endpoints are defined at: - /tts: https://github.com/google/voice-builder/blob/3a449a3e8d5100ff323161c89b897f6d5ccdb6f9/merlin_model_server/api.js#L34 - /alignment: https://github.com/google/voice-builder/blob/3a449a3e8d5100ff323161c89b897f6d5ccdb6f9/festival_model_server/api.js#L28 - /tts: https://github.com/google/voice-builder/blob/3a449a3e8d5100ff323161c89b897f6d5ccdb6f9/festival_model_server/api.js#L65. The attack vector is: Attacker sends a GET request to the vulnerable endpoint with a specially formatted query parameter. The fixed version is: After commit f6660e6d8f0d1d931359d591dbdec580fef36d36.
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Analysis
by VulDB Data Team • 11/06/2023
The vulnerability identified as CVE-2019-1010200 represents a critical operating system command injection flaw within Google's Voice Builder application, specifically manifesting as CWE-78 improper neutralization of special elements used in OS command execution. This vulnerability exists in two distinct web server components that expose three vulnerable endpoints, creating a significant attack surface for remote code execution. The affected system components operate with elevated privileges, meaning any successful exploitation would grant attackers the same level of access as the underlying server processes, potentially leading to complete system compromise. The vulnerability is particularly concerning because it affects multiple endpoints within the voice builder infrastructure, specifically targeting the text-to-speech and alignment functionalities that are integral to the application's core operations.
The technical exploitation mechanism involves attackers sending carefully crafted GET requests to the vulnerable endpoints, where specially formatted query parameters are processed without adequate sanitization or validation. This allows malicious input to be interpreted as command-line arguments and executed within the operating system context of the web server. The vulnerable endpoints include /tts and /alignment paths in both the merlin_model_server and festival_model_server components, with specific API implementations at the mentioned file locations. The injection occurs because user-supplied input flows directly into system command execution without proper parameter escaping or input validation, creating a direct pathway for arbitrary command execution. This type of vulnerability is classified under the ATT&CK framework as a command injection technique, specifically targeting operating system commands through web interfaces.
The operational impact of this vulnerability extends far beyond simple data theft, as it enables full remote code execution capabilities with server-level privileges. Attackers could potentially install backdoors, exfiltrate sensitive data, modify system configurations, or use the compromised server as a launch point for further attacks within the network infrastructure. The exposure of multiple endpoints increases the likelihood of successful exploitation, as attackers have several potential vectors to target. The vulnerability affects the entire voice builder ecosystem, including both the merlin and festival model servers, which are fundamental components for voice synthesis and alignment processing. Given that these are web-accessible endpoints, the attack surface is easily accessible from external networks without requiring additional authentication or privilege escalation.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and sanitization mechanisms across all affected endpoints. The fix implemented in the subsequent commit addresses the root cause by ensuring that user-supplied parameters are properly escaped or filtered before being incorporated into system commands. Organizations should enforce strict parameter validation, implement proper input encoding, and utilize secure coding practices that prevent command injection vulnerabilities. Additionally, network segmentation and access controls should be implemented to limit exposure of these vulnerable endpoints, while regular security audits should verify that similar vulnerabilities do not exist in other parts of the application. The fix aligns with industry best practices for preventing OS command injection attacks and demonstrates the importance of input validation in web application security.