CVE-2001-0494 in IMail
Summary
by MITRE
Buffer overflow in IPSwitch IMail SMTP server 6.06 and possibly prior versions allows remote attackers to execute arbitrary code via a long From: header.
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Analysis
by VulDB Data Team • 10/06/2025
The vulnerability identified as CVE-2001-0494 represents a critical buffer overflow flaw in the IPSwitch IMail SMTP server version 6.06 and potentially earlier releases. This security weakness resides within the server's handling of email headers, specifically the From: field, which serves as a fundamental component in email communication protocols. The buffer overflow occurs when the server processes an excessively long From: header, causing memory corruption that can be exploited by remote attackers to gain unauthorized control over the affected system.
The technical implementation of this vulnerability stems from inadequate input validation within the IMail SMTP server's email processing routines. When an attacker crafts a malicious email message containing an overly long From: header, the server fails to properly bounds-check the input data before copying it into a fixed-size memory buffer. This classic buffer overflow condition allows the attacker to overwrite adjacent memory locations, potentially including return addresses, function pointers, or other critical program state information. The flaw operates at the application layer within the Simple Mail Transfer Protocol implementation, making it particularly dangerous as it can be triggered through standard email transmission methods without requiring special privileges or authentication.
The operational impact of this vulnerability extends far beyond simple data corruption, as successful exploitation can lead to complete system compromise and arbitrary code execution. Attackers can leverage this weakness to install backdoors, escalate privileges, access sensitive data, or use the compromised server as a launch point for further attacks within the network infrastructure. The remote nature of the exploit means that attackers do not need physical access to the server or local network connectivity, making it particularly attractive for widespread attacks. Organizations relying on IMail servers for email services face significant risk of unauthorized access, data breaches, and potential service disruption, with the vulnerability affecting systems across various industries including financial services, healthcare, and government sectors.
Mitigation strategies for this vulnerability should encompass multiple layers of security controls to address both immediate threats and prevent future exploitation attempts. The primary recommendation involves applying the official security patch provided by IPSwitch, which typically includes input validation enhancements and memory management improvements to prevent buffer overflow conditions. Network administrators should implement email filtering solutions that can detect and block malformed email headers, particularly those containing unusually long From: fields that exceed typical email header length limits. Additionally, system hardening measures such as disabling unnecessary email services, implementing strict email header validation policies, and deploying intrusion detection systems can provide additional protection layers. From a cybersecurity framework perspective, this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and maps to ATT&CK technique T1059.007 for command and script injection, demonstrating the multi-faceted nature of the threat landscape. Organizations should also consider implementing network segmentation to limit lateral movement capabilities if exploitation occurs, alongside comprehensive monitoring and incident response procedures to detect and respond to potential compromise attempts.