CVE-2001-0844 in Post-It!
Summary
by MITRE
Vulnerability in (1) Book of guests and (2) Post it! allows remote attackers to execute arbitrary code via shell metacharacters in the email parameter.
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Analysis
by VulDB Data Team • 10/03/2025
This vulnerability resides in the book of guests and post it components of a web application, representing a classic command injection flaw that enables remote attackers to execute arbitrary code on the target system. The vulnerability specifically manifests when the application fails to properly sanitize user input in the email parameter, allowing malicious actors to inject shell metacharacters that get interpreted and executed by the underlying operating system. The flaw operates at the application layer where user-supplied data flows directly into system commands without adequate validation or escaping mechanisms, creating a pathway for attackers to escalate privileges and gain full control over the affected system. This type of vulnerability falls under the CWE-77 category of command injection, which is categorized as a critical security weakness in the Common Weakness Enumeration framework. The attack vector leverages the principle of insufficient input sanitization, where the application trusts user input without proper verification, making it susceptible to exploitation through carefully crafted payloads that can manipulate the execution flow of system commands.
The operational impact of this vulnerability extends far beyond simple data theft, as successful exploitation can result in complete system compromise and persistent backdoor access. Attackers can leverage this flaw to execute system commands with the privileges of the web application user, potentially escalating to root or administrator access depending on the system configuration. The vulnerability enables attackers to perform reconnaissance activities, install malware, modify or delete critical system files, and establish persistent access through backdoors or reverse shells. This type of vulnerability is particularly dangerous in web applications where the web server typically runs with elevated privileges, creating a significant attack surface for privilege escalation and lateral movement within the network. The attack can be executed remotely without requiring any special privileges or authentication, making it a high-severity threat that can be exploited by anyone who can submit data to the vulnerable application, thus aligning with the ATT&CK framework's technique T1059 for command and scripting interpreter.
Mitigation strategies for this vulnerability require immediate implementation of input validation and output encoding mechanisms throughout the application code. The most effective approach involves implementing proper parameter sanitization and escaping of user input before it is processed or passed to system commands, which directly addresses the root cause of the vulnerability. Organizations should deploy web application firewalls and input validation rules to detect and block suspicious metacharacter sequences, while also implementing proper access controls and privilege separation to limit the damage potential of successful exploitation attempts. The implementation of secure coding practices including the use of parameterized queries and built-in escaping functions can prevent the execution of unintended commands. Additionally, regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other parts of the application, while system monitoring should be enhanced to detect unusual command execution patterns that may indicate exploitation attempts. The vulnerability demonstrates the critical importance of the principle of least privilege and proper input validation, as outlined in industry security standards and best practices for secure software development.