CVE-2016-10193 in espeak-ruby Gem
Summary
by MITRE
The espeak-ruby gem before 1.0.3 for Ruby allows remote attackers to execute arbitrary commands via shell metacharacters in a string to the speak, save, bytes or bytes_wav method in lib/espeak/speech.rb.
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Analysis
by VulDB Data Team • 10/24/2024
The CVE-2016-10193 vulnerability represents a critical command injection flaw in the espeak-ruby gem, a ruby library designed to interface with the eSpeak text-to-speech engine. This vulnerability exists within the gem's handling of user-supplied input in four specific methods: speak, save, bytes, and bytes_wav, all located in the lib/espeak/speech.rb file. The flaw stems from improper input validation and sanitization, allowing malicious actors to inject shell commands through specially crafted strings that are then executed by the underlying eSpeak system without adequate security controls.
The technical implementation of this vulnerability follows a classic command injection pattern where user input flows directly into shell execution contexts. When applications using the espeak-ruby gem pass unvalidated strings to these methods, the gem fails to properly escape or sanitize the input before passing it to the operating system shell. This creates an environment where attackers can insert shell metacharacters such as semicolons, pipes, or backticks that are interpreted by the shell, enabling arbitrary command execution on the affected system. The vulnerability is particularly dangerous because it operates at the system level, bypassing application-level security controls and potentially allowing full system compromise.
The operational impact of this vulnerability extends beyond simple command execution, as it can enable attackers to perform a wide range of malicious activities including privilege escalation, data exfiltration, system reconnaissance, and persistence establishment. The vulnerability affects any ruby application that utilizes the espeak-ruby gem for text-to-speech functionality, making it particularly concerning for web applications, automated systems, and services that accept user input for speech synthesis. From an attacker's perspective, this vulnerability aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, representing a significant vector for initial access and lateral movement within compromised environments.
Security practitioners should note that this vulnerability maps directly to CWE-77, Command Injection, which is classified as a high-risk weakness in the CWE catalog. The flaw demonstrates poor input validation practices and highlights the importance of proper sanitization of user-supplied data before system-level operations. Mitigation strategies should include immediate upgrade to espeak-ruby version 1.0.3 or later, which contains proper input validation and sanitization measures. Additional defensive measures include implementing input filtering, using parameterized interfaces, and employing application firewalls to monitor for suspicious command patterns. Organizations should also conduct comprehensive vulnerability assessments to identify all systems using this gem and ensure proper patch management protocols are in place to prevent similar issues in other components of their software ecosystem.