CVE-2003-1014 in Security Gateway
Summary
by MITRE
Multiple content security gateway and antivirus products allow remote attackers to bypass content restrictions via MIME messages that use multiple MIME fields with the same name, which may be interpreted differently by mail clients.
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Analysis
by VulDB Data Team • 07/08/2017
This vulnerability exists in multiple content security gateway and antivirus products that process email messages through MIME (Multipurpose Internet Mail Extensions) format. The flaw stems from how these security systems handle MIME messages containing multiple fields with identical names, creating a potential bypass mechanism for malicious content that would otherwise be blocked. The vulnerability specifically affects the parsing logic of these security appliances, which may interpret duplicate MIME fields differently than standard mail clients, leading to inconsistent content evaluation and potential security breaches. This issue represents a classic case of improper input validation and processing within security gateways that are designed to enforce content restrictions and prevent malicious email traffic from reaching end users.
The technical implementation of this vulnerability exploits the inconsistent handling of MIME field duplication across different email processing systems. When a malicious actor crafts an email message with multiple MIME fields sharing the same name, the security gateway may process these fields in a manner that differs from standard mail client interpretation. This discrepancy allows attackers to inject content that bypasses security checks because the gateway's parsing logic fails to properly normalize or validate duplicate fields. The vulnerability specifically targets the message parsing engine of content security appliances, where the system's failure to properly handle MIME field duplication creates a window for bypassing content filtering rules. This type of vulnerability commonly falls under CWE-1299, which addresses improper handling of duplicate fields in structured data formats, and relates to ATT&CK technique T1190 for exploitation of vulnerabilities in network infrastructure.
The operational impact of this vulnerability is significant as it allows remote attackers to circumvent content security policies implemented by organizations. Security administrators may believe that their content filtering systems are properly blocking malicious content when in reality attackers can craft messages that exploit this parsing inconsistency to deliver harmful payloads. The vulnerability affects organizations that rely on email security appliances for protection against spam, malware, and policy violations, potentially leading to data breaches, malware infections, and unauthorized access to corporate networks. Organizations may experience false security confidence due to the bypass mechanism, while the actual security posture remains compromised. The vulnerability can be particularly dangerous in enterprise environments where email is a primary vector for attacks, as it undermines the fundamental purpose of content security gateways to enforce organizational security policies.
Mitigation strategies for this vulnerability require immediate attention to the affected security appliances and implementation of proper MIME field handling protocols. Organizations should ensure that all content security gateways are updated with patches that address the duplicate MIME field parsing issue, typically through enhanced input validation and normalization of MIME structures. Security administrators should implement additional monitoring and logging mechanisms to detect unusual MIME field patterns that might indicate exploitation attempts. Network security teams should consider implementing redundant content filtering systems that can cross-validate message parsing results to detect inconsistencies between different security appliances. Regular security assessments should include testing for similar parsing inconsistencies in other email processing systems and network infrastructure components. The fix typically involves updating the MIME parsing engine to properly handle duplicate field scenarios according to standard email protocol specifications, ensuring consistent interpretation across all security systems.