CVE-2000-0932 in MAILsweeper for SMTP
Summary
by MITRE
MAILsweeper for SMTP 3.x does not properly handle corrupt CDA documents in a ZIP file and hangs, which allows remote attackers to cause a denial of service.
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Analysis
by VulDB Data Team • 04/06/2019
The vulnerability identified as CVE-2000-0932 affects MAILsweeper for SMTP version 3.x, a mail filtering and security solution designed to protect email systems from malicious content. This issue manifests when the software encounters corrupt CDA documents embedded within ZIP archives during the email scanning process. The flaw represents a classic denial of service condition where the application fails to properly validate or handle malformed data structures, leading to system hanging and unresponsiveness.
The technical root cause of this vulnerability lies in the improper handling of compressed archive contents within the email filtering pipeline. When MAILsweeper for SMTP processes incoming emails containing ZIP files with corrupted CDA (Common Data Access) documents, the application's decompression and content parsing mechanisms fail to implement adequate error handling or boundary checking. This failure results in the application entering an infinite loop or resource exhaustion state, effectively causing the service to hang and become unavailable to legitimate users.
From an operational impact perspective, this vulnerability presents a significant risk to email service availability and business continuity. Remote attackers can exploit this weakness by crafting specially formatted emails containing maliciously constructed ZIP archives with corrupt CDA documents, thereby triggering the denial of service condition without requiring authentication or privileged access. The vulnerability affects the core functionality of the email security system, potentially disrupting critical communication channels and requiring manual intervention to restore service.
The flaw aligns with CWE-400, which addresses unchecked resource allocation or processing in software systems, and demonstrates poor input validation practices that are commonly exploited in denial of service attacks. This vulnerability also maps to ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion or application hanging. Organizations relying on MAILsweeper for SMTP 3.x should implement immediate mitigations including patching to the latest available version, implementing network-level filtering to block suspicious email attachments, and deploying additional monitoring to detect unusual service behavior patterns. The vulnerability underscores the importance of robust error handling and input validation in security applications where malformed data could lead to complete service disruption, emphasizing the need for defensive programming practices and comprehensive testing of edge cases in email processing systems.