CVE-2007-6676 in Uber Uploader
Summary
by MITRE
The default configuration of Uber Uploader (UU) 5.3.6 and earlier does not block uploads of (1) .html, (2) .asp, and other possibly dangerous extensions, which allows remote attackers to use these extensions in uploads via (a) uu_file_upload.php, related to uu_file_upload.js and (b) uber_uploader_file.php, related to uber_uploader_file.js, a different issue than CVE-2007-0123. NOTE: the vendor disputes the severity of the issue, noting that it is the administrator s responsibility to "add file extensions that you may or may not want uploaded."
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Analysis
by VulDB Data Team • 11/06/2017
The vulnerability identified as CVE-2007-6676 affects Uber Uploader version 5.3.6 and earlier, representing a critical security flaw in the default configuration of this file upload utility. This issue stems from insufficient input validation and improper file extension filtering mechanisms within the upload processing scripts. The vulnerability specifically permits the upload of potentially dangerous file types including .html and .asp extensions, which can be exploited by remote attackers to execute malicious code or compromise the target system. The affected components include uu_file_upload.php and uber_uploader_file.php, along with their corresponding javascript files uu_file_upload.js and uber_uploader_file.js, creating multiple attack vectors for exploitation.
The technical flaw manifests in the application's failure to implement comprehensive file extension validation during the upload process. This weakness directly maps to CWE-434, which describes insecure file upload vulnerabilities where applications accept files without proper validation of their content or type. The vulnerability allows attackers to bypass security controls by uploading files with extensions that could execute server-side code or contain malicious content. When .html files are uploaded, they can potentially serve as cross-site scripting vectors, while .asp files could execute server-side scripts if the hosting environment permits such execution. The attack surface is expanded through the multiple entry points provided by the different php and javascript files in the upload chain.
The operational impact of this vulnerability is significant as it creates opportunities for attackers to perform persistent code execution and maintain access to compromised systems. Remote attackers can leverage this weakness to upload malicious files that may contain web shells, backdoors, or other malicious payloads that can be executed within the target environment. The vulnerability essentially undermines the security posture of any system using the default Uber Uploader configuration, as it allows unauthorized file uploads without proper security restrictions. This type of vulnerability can lead to complete system compromise, data exfiltration, and persistent access for attackers, making it particularly dangerous in enterprise environments where the software may be used without proper security hardening.
Organizations should implement multiple layers of defense to mitigate this vulnerability, including proper file extension filtering, content type validation, and mandatory file scanning before upload acceptance. The recommended approach involves configuring the application to explicitly deny uploads of dangerous extensions such as .asp, .html, .php, .pl, .cgi, and other potentially harmful file types. Administrators should also implement proper file content validation to ensure uploaded files match their claimed extensions. According to ATT&CK framework, this vulnerability relates to T1190 - Exploit Public-Facing Application and T1059 - Command and Scripting Interpreter, as attackers can exploit the upload functionality to execute malicious commands on the target system. The vendor's stance that administrators are responsible for adding restrictions is problematic, as default configurations should provide reasonable security out-of-the-box, aligning with security best practices and the principle of least privilege.