CVE-2004-2619 in ripMIME
Summary
by MITRE
ripMIME 1.3.2.3 and earlier allows remote attackers to bypass e-mail protection via a base64 MIME encoded attachment containing invalid characters that are not properly extracted.
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Analysis
by VulDB Data Team • 07/01/2021
The vulnerability described in CVE-2004-2619 affects ripMIME version 1.3.2.3 and earlier, representing a critical flaw in email security software designed to protect against malicious attachments. This issue stems from improper handling of base64 encoded MIME attachments, specifically when invalid characters are present within the encoded content. The vulnerability resides in the software's inability to properly sanitize and extract base64 encoded data, creating a pathway for attackers to circumvent email protection mechanisms.
The technical implementation of this flaw involves the ripMIME software's insufficient validation of base64 encoded content during MIME parsing operations. When processing email attachments, the system fails to properly handle invalid base64 characters that may be embedded within otherwise legitimate encoded content. This improper extraction mechanism allows attackers to craft malicious attachments that contain invalid base64 characters which are silently ignored or improperly processed by the software, effectively bypassing the intended security controls. The vulnerability operates at the MIME parsing layer where base64 decoding routines do not adequately validate character sets or handle malformed encoding sequences.
From an operational perspective, this vulnerability creates significant risk for organizations relying on ripMIME for email security protection. Attackers can exploit this weakness to deliver malicious payloads that would normally be detected and blocked by proper MIME validation. The bypass capability means that even properly configured email security systems using this software may be rendered ineffective against certain attack vectors. This vulnerability directly impacts the integrity of email security policies and can lead to unauthorized access to systems through phishing campaigns or direct malware delivery attempts. The flaw essentially undermines the core security premise of email attachment filtering by allowing malformed content to slip through validation mechanisms.
The vulnerability aligns with CWE-20, "Improper Input Validation," and CWE-770, "Allocation of Resources Without Limits or Throttling," as it involves improper handling of input data and potential resource exhaustion through malformed attachment processing. From an ATT&CK framework perspective, this vulnerability maps to T1192, "Phishing with Spoofed Delivery" and T1078, "Valid Accounts," as attackers can use the bypass to deliver malicious content that appears legitimate while exploiting the software's failure to properly validate encoded content. Organizations should implement immediate patches to address this vulnerability, as the software versions affected are outdated and no longer supported. Additionally, network administrators should consider implementing additional email security layers including content filtering, sandboxing, and advanced threat detection mechanisms to compensate for the bypass capability while awaiting official patches. The vulnerability underscores the importance of proper input sanitization and validation in security software, particularly in email processing systems where malformed content can represent serious security risks.