CVE-2005-3573 in Mailman
Summary
by MITRE
Scrubber.py in Mailman 2.1.5-8 does not properly handle UTF8 character encodings in filenames of e-mail attachments, which allows remote attackers to cause a denial of service (application crash).
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 06/15/2019
The vulnerability described in CVE-2005-3573 affects Mailman version 2.1.5 through 2.1.8 where the scrubber.py component fails to properly manage UTF-8 character encodings in email attachment filenames. This flaw exists within the email processing pipeline of the Mailman mailing list manager system, which is widely used for managing email distribution lists in organizational and open source environments. The issue manifests when the system encounters email attachments with UTF-8 encoded filenames that contain non-standard or malformed character sequences, leading to application instability and potential service disruption.
The technical root cause of this vulnerability lies in improper input validation and encoding handling within the scrubber.py module. When Mailman processes incoming emails with attachments containing UTF-8 encoded filenames, the application fails to properly sanitize or handle these character sequences, resulting in a crash condition. This represents a classic buffer overflow or encoding error scenario where the application does not adequately validate the encoding format of filenames before processing them. The vulnerability specifically targets the filename parsing mechanism within the email attachment handling code, which falls under CWE-180, "Incorrect Behavior Order" and CWE-707, "Improper Neutralization of Input During Web Page Generation". The flaw demonstrates inadequate error handling for internationalized character sets that are commonly used in modern email systems.
The operational impact of this vulnerability extends beyond simple application instability to potentially disrupt email services for entire mailing lists and organizations relying on Mailman. Remote attackers can exploit this weakness by sending specially crafted emails with malformed UTF-8 filenames, causing the Mailman service to crash and restart repeatedly. This denial of service condition can render mailing lists unavailable for legitimate users, potentially affecting communication channels for critical business operations or open source projects. The vulnerability is particularly concerning in environments where automated email processing is critical, as the service disruption can cascade into broader operational issues. According to ATT&CK framework, this represents a Denial of Service attack pattern under T1499.004, "Endpoint Denial of Service" and T1566.002, "Phishing with Social Engineering" as attackers may use this vulnerability to target specific mailing list administrators through malicious email payloads.
Organizations using affected Mailman versions should implement immediate mitigations including upgrading to patched versions of Mailman 2.1.9 or later, which contain proper UTF-8 encoding validation and error handling mechanisms. System administrators should also consider implementing email filtering rules that can detect and quarantine emails with suspicious filename encodings before they reach the Mailman processing engine. Additional protective measures include monitoring for service restarts and implementing automated alerting for unusual application crash patterns. The fix implemented in later versions addresses the core encoding handling issue by introducing proper UTF-8 validation routines and graceful error handling for malformed filenames, preventing the application from crashing when encountering unexpected character sequences. Security teams should also review their email security policies to ensure that international character sets are properly handled in all email processing systems and that appropriate input sanitization measures are in place to prevent similar encoding-related vulnerabilities in other components of their email infrastructure.