CVE-2018-7665 in ClipBucket
Summary
by MITRE
An issue was discovered in ClipBucket before 4.0.0 Release 4902. A malicious file can be uploaded via the name parameter to actions/beats_uploader.php or actions/photo_uploader.php, or the coverPhoto parameter to edit_account.php.
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Analysis
by VulDB Data Team • 01/10/2020
The vulnerability identified as CVE-2018-7665 represents a critical file upload flaw in ClipBucket version 4.0.0 Release 4902 and earlier. This issue stems from inadequate input validation and sanitization mechanisms within the application's file handling processes. The vulnerability manifests through three distinct upload endpoints: actions/beats_uploader.php, actions/photo_uploader.php, and the edit_account.php script's coverPhoto parameter. These endpoints fail to properly validate file types, extensions, or content, creating opportunities for attackers to bypass security controls and execute malicious code within the target environment.
The technical exploitation of this vulnerability involves crafting malicious files that can be uploaded through the vulnerable parameters, allowing attackers to potentially execute arbitrary code on the server. This type of vulnerability falls under CWE-434, which specifically addresses "Unrestricted Upload of File with Dangerous Type," a well-documented weakness in web applications that fail to properly validate file uploads. The flaw enables attackers to upload files with extensions such as .php, .asp, or other executable formats that can be executed by the web server, effectively granting remote code execution capabilities. The vulnerability's impact is amplified by the fact that it affects multiple upload endpoints, increasing the attack surface and providing multiple vectors for exploitation.
From an operational standpoint, this vulnerability presents significant risks to ClipBucket installations, potentially allowing attackers to gain full control over affected servers. The impact extends beyond simple code execution to include data theft, service disruption, and potential lateral movement within networks. Attackers could upload web shells or backdoors that persist across server reboots, enabling long-term unauthorized access to the compromised system. The vulnerability also aligns with ATT&CK technique T1190, "Exploit Public-Facing Application," as it represents an exploitable weakness in a publicly accessible web application. Organizations running affected versions of ClipBucket face potential exposure to credential theft, data breaches, and complete system compromise, making this vulnerability particularly dangerous for content management systems hosting sensitive user data.
Mitigation strategies for CVE-2018-7665 must focus on implementing robust file validation mechanisms and restricting upload capabilities. Organizations should immediately upgrade to ClipBucket version 4.0.0 Release 4902 or later, which contains the necessary patches to address this vulnerability. Additionally, administrators should implement strict file type validation by whitelisting allowed extensions and rejecting uploads of executable files. The solution should include server-side validation of file content, not just extensions, using techniques such as MIME type checking and file signature verification. Network-level protections such as web application firewalls can provide additional defense-in-depth, though they should not be relied upon as the sole mitigation. Regular security audits of upload endpoints and implementation of least privilege principles for file upload directories are essential components of a comprehensive security strategy. The vulnerability also underscores the importance of following secure coding practices and implementing proper input sanitization as outlined in OWASP Top Ten security guidelines.