CVE-2008-3047 in Kb Unpack Extension
Summary
by MITRE
Incomplete blacklist vulnerability in the KB Unpack (kb_unpack) extension 0.1.0 and earlier for TYPO3 has unknown impact and attack vectors.
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Analysis
by VulDB Data Team • 11/21/2017
The CVE-2008-3047 vulnerability represents a critical security flaw in the KB Unpack extension version 0.1.0 and earlier for the TYPO3 content management system. This vulnerability stems from an incomplete blacklist implementation that fails to properly validate file types and upload restrictions, creating a potential pathway for malicious file execution within the TYPO3 environment. The vulnerability specifically affects the extension's handling of file uploads and processing, where the system relies on a limited blacklist approach rather than a comprehensive whitelist validation mechanism.
The technical flaw manifests in the extension's insufficient input validation processes where it fails to adequately check file extensions, MIME types, or file content before processing uploads. This incomplete blacklist approach means that attackers can potentially bypass restrictions by using file names or extensions that are not explicitly listed in the validation rules. The vulnerability's nature aligns with CWE-20, which describes improper input validation, and CWE-434, which covers unrestricted upload of files with dangerous types. The attack surface is particularly concerning as it operates at the file upload level where successful exploitation could lead to arbitrary code execution or full system compromise.
The operational impact of this vulnerability extends beyond simple file upload restrictions, as it creates a persistent security risk within TYPO3 installations that utilize the affected KB Unpack extension. Attackers could potentially upload malicious files such as web shells, malware, or other exploit payloads that would execute within the context of the web server. The unknown attack vectors component indicates that the specific methods of exploitation may not have been fully documented or understood at the time of reporting, making the vulnerability particularly dangerous as defenders cannot predict all possible attack scenarios. This type of vulnerability directly maps to ATT&CK technique T1190, which covers exploiting vulnerabilities in web applications, and T1059, which covers command and scripting interpreters.
Organizations using affected TYPO3 versions should immediately implement multiple layers of mitigation strategies to address this vulnerability. The primary remediation involves updating to a patched version of the KB Unpack extension or implementing a comprehensive whitelist approach for file uploads that validates against known safe file types and extensions. Additional security measures should include restrictive file permissions, web server configuration hardening, and monitoring for suspicious file upload activities. The vulnerability highlights the critical importance of proper input validation and the dangers of relying solely on blacklist approaches for security controls, as demonstrated by the principle of least privilege and defense in depth strategies recommended by security frameworks such as NIST SP 800-53.