CVE-2001-0216 in WebPALS
Summary
by MITRE
PALS Library System pals-cgi program allows remote attackers to execute arbitrary commands via shell metacharacters in the documentName parameter.
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Analysis
by VulDB Data Team • 10/08/2025
The vulnerability identified as CVE-2001-0216 affects the PALS Library System's pals-cgi program, representing a critical command injection flaw that enables remote attackers to execute arbitrary system commands. This vulnerability resides within the documentName parameter processing functionality of the web-based interface, where insufficient input validation allows malicious actors to inject shell metacharacters that are subsequently interpreted and executed by the underlying operating system. The flaw demonstrates characteristics consistent with CWE-77, which specifically addresses command injection vulnerabilities where user-supplied data is improperly incorporated into shell commands without adequate sanitization or escaping mechanisms.
The technical implementation of this vulnerability exploits the insecure handling of user input within the pals-cgi program's parameter processing logic. When the documentName parameter contains shell metacharacters such as semicolons, ampersands, or backticks, these characters are interpreted by the system shell and executed as part of the command sequence. This represents a classic example of improper input validation and output encoding that allows attackers to bypass normal security controls and gain unauthorized access to system resources. The vulnerability operates at the application layer and can be exploited through HTTP requests without requiring any special privileges or authentication, making it particularly dangerous for publicly accessible web applications.
The operational impact of this vulnerability extends beyond simple command execution to encompass potential system compromise and data breaches. Attackers can leverage this flaw to perform a wide range of malicious activities including but not limited to executing system commands, accessing sensitive files, modifying system configurations, or establishing persistent access through backdoor creation. The vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, where adversaries use legitimate system tools to execute commands. Additionally, the vulnerability enables privilege escalation scenarios where attackers can potentially elevate their privileges to gain administrative access to the underlying system, particularly if the web application runs with elevated permissions.
Mitigation strategies for CVE-2001-0216 must address both immediate remediation and long-term architectural improvements to prevent similar vulnerabilities. The primary solution involves implementing proper input validation and sanitization of all user-supplied parameters, particularly those that are directly incorporated into system commands. This includes employing parameterized command execution where user input is properly escaped or quoted to prevent shell interpretation, and implementing strict input filtering that removes or encodes dangerous metacharacters. Organizations should also consider implementing web application firewalls to detect and block suspicious command injection patterns, and ensure that the pals-cgi program runs with minimal required privileges to limit potential damage from successful exploitation. The remediation approach should follow security best practices outlined in OWASP Top 10 and NIST guidelines for preventing command injection vulnerabilities, emphasizing defense in depth strategies that include input validation, output encoding, and proper privilege management.