CVE-2000-1130 in WebShield SMTP
Summary
by MITRE
McAfee WebShield SMTP 4.5 allows remote attackers to bypass email content filtering rules by including Extended ASCII characters in name of the attachment.
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Analysis
by VulDB Data Team • 10/11/2025
The vulnerability identified as CVE-2000-1130 represents a significant security flaw in McAfee WebShield SMTP version 4.5 that directly impacts email content filtering mechanisms. This issue specifically targets the handling of file attachments within email messages, creating a pathway for malicious actors to circumvent protective measures designed to block harmful content. The vulnerability exploits a fundamental weakness in how the system processes and validates attachment names, particularly when Extended ASCII characters are present in the filename. Extended ASCII characters, which fall outside the standard 7-bit ascii range, are often processed differently by various email systems and can trigger parsing inconsistencies that allow attackers to evade detection.
The technical flaw manifests when the WebShield SMTP system encounters attachment names containing Extended ASCII characters that are not properly normalized or filtered during the content inspection process. This parsing inconsistency enables attackers to craft email attachments with filenames that contain characters which bypass the system's filtering rules while still maintaining the functional integrity of the malicious payload. The vulnerability operates at the protocol level where email content is inspected and filtered, specifically targeting the boundary conditions in how filenames are processed and validated. This type of vulnerability falls under the CWE category of improper input validation, specifically CWE-20, which addresses weakness in input sanitization and validation processes. The attack vector is particularly concerning as it requires no authentication or privileged access, making it a remote exploit that can be executed from anywhere on the network.
The operational impact of this vulnerability extends beyond simple bypass of content filtering rules to potentially enable more severe security incidents within corporate email environments. When attackers successfully exploit this weakness, they can deliver malicious attachments that would normally be blocked by the content filtering system, potentially leading to malware distribution, data exfiltration, or other malicious activities. The vulnerability undermines the fundamental security posture of organizations relying on McAfee WebShield for email protection, as it creates a covert channel for malicious content that can bypass multiple layers of security controls. This weakness particularly affects organizations with strict email policies and content filtering requirements, where the integrity of email security measures is paramount for protecting against phishing attacks, malware delivery, and other email-based threats.
Organizations should implement immediate mitigations including updating to patched versions of McAfee WebShield SMTP, implementing additional email content validation mechanisms, and conducting thorough security assessments of their email filtering systems. The ATT&CK framework categorizes this type of vulnerability under T1566 - Phishing, as it enables attackers to bypass email security controls to deliver malicious payloads. Security administrators should also consider implementing additional monitoring and logging of email attachment processing to detect potential exploitation attempts. The vulnerability demonstrates the critical importance of comprehensive input validation and the need for robust sanitization of all user-supplied data in email systems. Organizations must also ensure that their email security solutions properly handle all character sets and encoding methods to prevent similar bypass scenarios. Regular security testing and vulnerability assessments should include evaluation of content filtering systems to identify potential parsing inconsistencies that could be exploited by threat actors.