CVE-2001-0956 in SpeechD
Summary
by MITRE
speechd 0.54 and earlier, with the Festival or rsynth speech synthesis package, allows attackers to execute arbitrary commands via shell metacharacters.
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Analysis
by VulDB Data Team • 01/17/2025
The vulnerability identified as CVE-2001-0956 affects speechd versions 0.54 and earlier when configured to use either the Festival or rsynth speech synthesis packages. This represents a critical command injection flaw that enables remote attackers to execute arbitrary system commands through carefully crafted input containing shell metacharacters. The vulnerability stems from insufficient input validation and sanitization within the speech synthesis processing pipeline, where user-provided text intended for speech conversion is directly passed to shell commands without proper escaping or filtering.
The technical implementation of this vulnerability occurs at the interface between the speech synthesis engine and the underlying shell execution environment. When speechd processes text input for speech generation, it constructs shell commands that invoke either the Festival or rsynth programs. If the input contains shell metacharacters such as semicolons, ampersands, or backticks, these characters are interpreted by the shell and executed as additional commands rather than being treated as literal text. This creates a classic command injection attack vector that can be exploited to gain unauthorized system access and execute malicious operations.
From an operational impact perspective, this vulnerability presents a significant security risk to systems running affected speechd versions, particularly those exposed to untrusted input sources. Attackers can leverage this flaw to execute arbitrary commands with the privileges of the speechd process, which typically runs with elevated permissions to access system audio devices and speech synthesis resources. The implications extend beyond simple command execution to potential privilege escalation, system compromise, and data exfiltration. The vulnerability affects both local and remote attack scenarios, making it particularly dangerous in networked environments where speech services are exposed to external users or applications.
The vulnerability maps to CWE-78, which specifically addresses "Improper Neutralization of Special Elements used in an OS Command," and aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter. Mitigation strategies should focus on input validation and sanitization, implementing proper escaping of shell metacharacters before command execution. Organizations should immediately upgrade to speechd versions 0.55 or later where this vulnerability has been patched, while also implementing network segmentation to limit exposure of speech services to untrusted networks. Additional protective measures include running the speechd service with minimal required privileges, implementing input filtering at multiple layers, and monitoring for suspicious command execution patterns in system logs. The patch for this vulnerability specifically addresses the improper handling of shell metacharacters in command construction, ensuring that all user input is properly escaped before being passed to shell execution functions.