CVE-2001-1373 in ZoneAlarm
Summary
by MITRE
MailSafe in Zone Labs ZoneAlarm 2.6 and earlier and ZoneAlarm Pro 2.6 and 2.4 does not block prohibited file types with long file names, which allows remote attackers to send potentially dangerous attachments.
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Analysis
by VulDB Data Team • 05/31/2018
The vulnerability described in CVE-2001-1373 represents a critical flaw in the email security filtering mechanisms of Zone Labs ZoneAlarm firewall software versions 2.6 and earlier, including both the standard ZoneAlarm and ZoneAlarm Pro variants. This weakness specifically affects the MailSafe component which is designed to scan and block potentially malicious email attachments before they reach the user's inbox. The flaw exploits a fundamental gap in the file type validation process where the system fails to properly identify and block dangerous file extensions when they are embedded within long filename structures.
The technical implementation of this vulnerability stems from inadequate input validation within the MailSafe module's file name parsing logic. When email attachments contain file extensions that exceed standard naming conventions or utilize unusual filename formatting, the security system's detection algorithms fail to properly classify these as prohibited file types. This occurs because the filtering mechanism does not adequately handle edge cases in filename parsing, particularly when dealing with extended filename lengths that exceed typical boundaries. The vulnerability creates a bypass condition where malicious actors can craft email attachments using long filenames containing hidden or obfuscated dangerous extensions that would normally be blocked by the security system.
The operational impact of this vulnerability extends beyond simple file type blocking failures and represents a significant threat vector for remote attackers seeking to compromise systems through social engineering and email-based attacks. Attackers can exploit this weakness by sending specially crafted emails containing malicious attachments with long filenames that appear legitimate to the user while simultaneously bypassing the security filtering. This creates a dangerous scenario where users may inadvertently open attachments that contain malware, trojans, or other malicious code that would normally be prevented by the ZoneAlarm security system. The vulnerability essentially undermines the core security premise of the MailSafe component, which is to provide automated protection against dangerous email content.
This vulnerability aligns with CWE-20, which describes improper input validation, and demonstrates how insufficient validation of file name structures can create security bypass opportunities. The flaw also relates to ATT&CK technique T1193, which involves Spearphishing Attachments, as it enables attackers to more effectively deliver malicious payloads through email channels. Organizations using affected versions of ZoneAlarm would be particularly vulnerable during phishing campaigns where attackers attempt to evade detection by crafting attachments with extended filenames. The security implications extend to enterprise environments where email filtering is a critical component of overall security posture, potentially allowing attackers to establish initial footholds through compromised email systems.
The recommended mitigation strategies involve immediate upgrading to patched versions of ZoneAlarm software that address the filename validation issues within the MailSafe component. Organizations should also implement additional email security measures including multiple layers of content filtering, enhanced user education programs about suspicious email attachments, and regular security assessments of email handling procedures. Network administrators should consider implementing supplementary email security tools that provide independent verification of email attachments, as well as establishing clear policies for handling suspicious email content. Regular security updates and patch management processes should be reinforced to ensure that all security software components remain current with the latest threat intelligence and vulnerability fixes.