CVE-2000-0352 in Pine
Summary
by MITRE
Pine before version 4.21 does not properly filter shell metacharacters from URLs, which allows remote attackers to execute arbitrary commands via a malformed URL.
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Analysis
by VulDB Data Team • 04/19/2026
The vulnerability identified as CVE-2000-0352 represents a critical command injection flaw in the Pine email client software prior to version 4.21. This issue stems from inadequate input validation and sanitization mechanisms within the application's handling of Uniform Resource Locator (URL) parameters. The Pine client, which was widely used for email management and news reading in Unix-like environments, failed to properly escape or filter shell metacharacters present in URL strings, creating a pathway for malicious actors to exploit the system.
The technical exploitation of this vulnerability occurs when Pine processes URLs that contain specially crafted shell metacharacters such as semicolons, ampersands, or backticks. When these malformed URLs are processed by the application, the shell metacharacters are interpreted by the underlying operating system shell, allowing attackers to inject and execute arbitrary commands with the privileges of the user running the Pine client. This represents a classic command injection vulnerability that operates at the application layer, where user-supplied input flows directly into shell execution contexts without proper sanitization.
The operational impact of this vulnerability extends beyond simple command execution, as it provides attackers with potential access to the entire system where Pine is installed. Depending on the privileges of the user running the application, attackers could escalate their access to perform unauthorized operations including file manipulation, system reconnaissance, data exfiltration, or even establish persistent backdoors. The vulnerability affects environments where Pine is used in multi-user systems or web-based email interfaces, where users might encounter maliciously crafted URLs in email messages or news articles. This issue particularly impacts Unix and Linux systems where Pine was commonly deployed, making it a significant concern for system administrators managing email infrastructure.
The vulnerability aligns with CWE-78, which describes improper neutralization of special elements used in OS commands, and can be mapped to ATT&CK technique T1059.001 for command and scripting interpreter. Organizations affected by this vulnerability should immediately apply the patch released by the Pine development team for version 4.21, which implements proper input sanitization and shell metacharacter filtering. System administrators should also consider implementing network-level controls to restrict access to potentially malicious URLs and deploy intrusion detection systems to monitor for suspicious command execution patterns. Additionally, user education regarding the dangers of clicking on untrusted URLs and the importance of keeping software updated remains crucial in mitigating the risk of exploitation. The vulnerability demonstrates the importance of secure coding practices and input validation in preventing command injection attacks that can lead to complete system compromise.