CVE-2003-0928 in MAILsweeper
Summary
by MITRE
Clearswift MAILsweeper before 4.3.15 does not properly detect and filter RAR 3.20 encoded files, which allows remote attackers to bypass intended policy.
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Analysis
by VulDB Data Team • 06/30/2021
The vulnerability identified as CVE-2003-0928 affects Clearswift MAILsweeper versions prior to 4.3.15, representing a significant security flaw in email content filtering systems. This issue stems from inadequate detection mechanisms within the email security appliance that processes and inspects incoming email attachments. The flaw specifically targets RAR archive files using version 3.20 encoding, which are commonly used for compressing and packaging multiple files into a single archive for email transmission. Email security systems rely on accurate file type detection to enforce organizational policies and prevent malicious content from entering corporate networks through email channels.
The technical root cause of this vulnerability lies in the software's inability to properly identify and filter RAR 3.20 encoded files, creating a gap in the security inspection process. When RAR archives are processed by the MAILsweeper system, the software fails to recognize the specific encoding characteristics of version 3.20 archives, allowing them to pass through security controls undetected. This represents a failure in the application's file format recognition engine and content inspection capabilities, which are fundamental requirements for effective email security solutions. The vulnerability operates at the content inspection layer, where the system should be performing deep packet inspection and file type validation to prevent policy violations.
The operational impact of this vulnerability is substantial as it enables remote attackers to bypass security policies that are specifically designed to prevent the transmission of potentially harmful archive files through email channels. Attackers can exploit this weakness by embedding malicious payloads within RAR 3.20 encoded archives, which will be permitted to pass through the security controls. This creates a vector for malware distribution, data exfiltration attempts, and other malicious activities that organizations have specifically configured their email security systems to prevent. The vulnerability essentially renders the email security policy enforcement mechanism ineffective for this particular file type, undermining the overall security posture of organizations relying on the affected software.
Organizations utilizing Clearswift MAILsweeper versions before 4.3.15 face significant risks including potential malware infections, unauthorized data access, and compromise of network security controls. The vulnerability aligns with CWE-20, which describes improper input validation in software systems, and represents a failure in proper content filtering and validation processes. From an attack perspective, this flaw maps to techniques described in the MITRE ATT&CK framework under the category of "T1078 - Valid Accounts" and "T1059 - Command and Scripting Interpreter" as attackers can leverage the bypassed security controls to deliver malicious payloads that may execute commands on target systems. The security implications extend beyond immediate malware delivery to include potential privilege escalation and persistent access mechanisms that could be established through compromised email channels.
The recommended mitigation strategy involves immediate upgrading of Clearswift MAILsweeper installations to version 4.3.15 or later, which includes the necessary patches to properly detect and filter RAR 3.20 encoded files. Organizations should also implement additional monitoring and logging controls to detect anomalous email traffic patterns that might indicate exploitation attempts. Security administrators should review and update their email security policies to ensure comprehensive coverage of file type detection mechanisms, including regular validation of security appliance configurations. The vulnerability highlights the importance of maintaining up-to-date security software and the necessity of continuous security assessments to identify and remediate similar gaps in content filtering capabilities. Organizations should also consider implementing additional email security layers, such as sandboxing solutions, to provide defense-in-depth against similar vulnerabilities that may exist in other security controls.