CVE-2006-3523 in MIMEsweeper for Web
Summary
by MITRE
Clearswift MIMEsweeper for Web before 5.1.15 Hotfix allows remote attackers to cause a denial of service (crash) via an encrypted archived .RAR file, which triggers a scan error and causes the Web Policy Engine service to terminate.
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Analysis
by VulDB Data Team • 09/18/2017
The vulnerability identified as CVE-2006-3523 affects Clearswift MIMEsweeper for Web versions prior to 5.1.15 Hotfix, representing a significant denial of service weakness that can be exploited remotely by malicious actors. This flaw specifically targets the Web Policy Engine service component of the security solution, creating a scenario where legitimate system operations can be disrupted through carefully crafted malicious inputs. The vulnerability manifests when the system encounters an encrypted archived .RAR file during routine scanning operations, triggering an unhandled error condition that leads to service termination.
The technical implementation of this vulnerability stems from inadequate input validation and error handling mechanisms within the MIMEsweeper scanning engine. When processing encrypted .RAR archives, the system fails to properly handle the encryption-related metadata and file structure elements that are not properly supported by the current scanning logic. This represents a classic case of improper error handling as classified under CWE-704, where the application does not adequately manage exceptional conditions that arise during file processing operations. The flaw occurs at the point where the system attempts to analyze encrypted archive contents, specifically when it encounters the encryption headers and structures that differ from standard archive formats.
From an operational perspective, this vulnerability presents a substantial risk to organizations relying on Clearswift MIMEsweeper for Web as their primary email security solution. The remote exploitation capability means that attackers can trigger service disruptions without requiring physical access or local privileges, making the attack surface particularly wide. The impact extends beyond simple service interruption, as the termination of the Web Policy Engine service can leave email traffic unfiltered and potentially expose the organization to other security threats during the service outage period. This vulnerability directly maps to ATT&CK technique T1499.004, which involves network disruption and denial of service attacks targeting network infrastructure components.
The exploitation process requires minimal technical sophistication, as attackers only need to send an email containing an encrypted .RAR file to the target system. The vulnerability demonstrates how seemingly benign file processing operations can become attack vectors when proper error handling is absent from security solutions. Organizations utilizing affected versions of MIMEsweeper for Web face the risk of sustained service degradation or complete system unavailability, particularly in environments where email security is critical for business operations. The nature of the flaw suggests that similar vulnerabilities may exist in other archive processing components within the same security solution, highlighting the importance of comprehensive code review and testing.
Mitigation strategies for this vulnerability primarily involve applying the vendor-supplied patch or hotfix version 5.1.15, which addresses the specific error handling issue in the archive scanning module. System administrators should also implement additional monitoring and alerting mechanisms to detect unusual service termination patterns that might indicate exploitation attempts. Network-level protections such as email filtering rules that block .RAR attachments or encrypted archives can serve as temporary workarounds while permanent patches are deployed. The vulnerability underscores the importance of maintaining up-to-date security solutions and implementing robust input validation procedures across all file processing components, particularly those handling user-submitted content in security-critical applications.