CVE-2005-3287 in Mailsite Express
Summary
by MITRE
Incomplete blacklist vulnerability in Mailsite Express allows remote attackers to upload and possibly execute files via attachments with executable extensions such as ASPX, which are not converted to .TXT like other dangerous extensions, and which can be directly requested from the cache directory.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 07/28/2017
The vulnerability described in CVE-2005-3287 represents a critical security flaw in Mailsite Express email management software that stems from an incomplete security blacklist implementation. This issue specifically affects the software's handling of file attachments, where certain executable file extensions are not properly filtered or converted to safer formats like .TXT as other dangerous extensions are. The vulnerability exists within the application's content filtering mechanisms that are designed to prevent the execution of potentially harmful files through email attachments.
The technical exploitation of this vulnerability occurs through a specific attack vector involving file extensions such as ASPX that are not included in the software's comprehensive blacklist. While many dangerous file extensions are properly converted to .TXT format to prevent execution, ASPX files bypass this conversion process and remain as executable content. This oversight allows attackers to craft malicious email attachments using these specific extensions that can be directly requested from the cache directory, effectively bypassing the intended security controls. The vulnerability demonstrates a classic incomplete input validation issue where the security mechanism fails to account for all possible dangerous file types.
The operational impact of this vulnerability is significant as it provides remote attackers with a pathway to execute arbitrary code on systems running Mailsite Express. When users access email messages containing these malicious attachments, the system processes them through its caching mechanism, allowing the ASPX files to be cached and subsequently requested directly. This creates a persistent threat vector where attackers can upload malicious files that remain executable even after initial processing. The vulnerability essentially undermines the core security principle of least privilege by allowing unauthorized code execution through legitimate email handling processes.
The security implications extend beyond simple file execution to encompass broader system compromise potential. This vulnerability aligns with CWE-20, which addresses "Improper Input Validation" and represents a specific case of incomplete blacklist implementation. From an attack perspective, this flaw maps to several ATT&CK techniques including T1190 for Exploit Public-Facing Application and T1059 for Command and Scripting Interpreter, as attackers can leverage the cached ASPX files to execute malicious commands. The vulnerability also reflects poor secure coding practices related to security configuration management and input sanitization.
Mitigation strategies for this vulnerability require immediate implementation of comprehensive security patches provided by the vendor, along with manual configuration updates to ensure all potentially dangerous file extensions are properly blacklisted. Organizations should implement additional network-level controls such as deep packet inspection and web application firewalls to monitor and block requests for suspicious file types. The remediation process must include thorough testing to ensure that all executable extensions are properly handled, and the cache directory access controls should be reviewed to prevent direct file retrieval. Regular security assessments should verify that the blacklist is complete and up-to-date with current threat intelligence to prevent similar issues from arising in the future.