CVE-2001-0357 in FormMail
Summary
by MITRE
FormMail.pl in FormMail 1.6 and earlier allows a remote attacker to send anonymous email (spam) by modifying the recipient and message parameters.
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Analysis
by VulDB Data Team • 10/06/2025
The vulnerability identified as CVE-2001-0357 represents a critical security flaw in the FormMail.pl script version 1.6 and earlier, which operates as a web-based contact form processing utility. This issue stems from inadequate input validation and parameter handling within the script's email sending functionality, creating an avenue for malicious actors to exploit the system for unauthorized email transmission. The vulnerability is categorized under CWE-20, which addresses improper input validation, and specifically relates to CWE-74, which deals with injection flaws in email systems. The flaw exists in the manner in which the script processes user-supplied parameters, particularly those related to email recipients and message content, allowing attackers to manipulate the script's behavior through direct parameter modification.
The technical implementation of this vulnerability enables remote attackers to bypass normal email sending restrictions by directly modifying the recipient address and message parameters within the script's input handling mechanism. When users submit forms through the vulnerable FormMail.pl script, the application processes the provided parameters without sufficient sanitization or validation of the recipient field. This oversight allows attackers to inject arbitrary email addresses into the recipient parameter, effectively enabling them to send emails from the server to any destination without proper authorization. The vulnerability is particularly concerning because it operates at the application layer, where attackers can leverage web-based interfaces to manipulate script parameters and execute unauthorized email transmission.
The operational impact of CVE-2001-0357 extends beyond simple spam generation, creating significant security implications for organizations using vulnerable FormMail installations. Attackers can utilize this vulnerability to send phishing emails, distribute malware through email attachments, or conduct spam campaigns that may damage the organization's reputation and potentially violate anti-spam legislation such as CAN-SPAM Act provisions. The ability to send anonymous emails through this vulnerability makes it particularly attractive for malicious actors seeking to obscure their identity while conducting email-based attacks. This flaw also aligns with ATT&CK technique T1192, which involves the use of malicious email content to compromise systems, and represents a form of email injection that can be leveraged for various social engineering attacks. The vulnerability's exploitation does not require specialized tools or deep technical knowledge, making it accessible to a broad range of threat actors.
Organizations affected by this vulnerability should implement immediate mitigations including updating to FormMail versions 1.7 or later, which contain proper input validation and parameter sanitization. The recommended approach involves implementing strict input validation for all user-supplied parameters, particularly those related to email addresses and message content. Security measures should include validating recipient addresses against a predefined whitelist, implementing proper parameter sanitization, and restricting direct user input to email parameters. Additionally, organizations should consider implementing email rate limiting mechanisms and monitoring for unusual email sending patterns. The vulnerability demonstrates the critical importance of proper input validation and parameter handling in web applications, as outlined in OWASP Top 10 2017 category a03, which addresses injection flaws. Organizations should also review their web application security practices and implement comprehensive input validation across all script parameters to prevent similar vulnerabilities from occurring in other applications.