CVE-2007-4913 in IP.Board
Summary
by MITRE
ips_kernel/class_upload.php in Invision Power Board (IPB or IP.Board) 2.3.1 up to 20070912 allows remote attackers to upload arbitrary script files with crafted image filenames to uploads/, where they are saved with a .txt extension and are not executable. NOTE: there are limited usage scenarios under which this would be a vulnerability, but it is being tracked by CVE since the vendor has stated it is security-relevant.
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Analysis
by VulDB Data Team • 10/30/2017
The vulnerability identified as CVE-2007-4913 affects Invision Power Board versions up to 20070912, specifically within the ips_kernel/class_upload.php component. This issue represents a file upload vulnerability that could potentially allow remote attackers to execute malicious code on affected systems. The vulnerability is particularly concerning because it involves the handling of user-uploaded files in the uploads/ directory, which could provide attackers with a pathway to compromise the web application and underlying server infrastructure.
The technical flaw stems from improper validation and handling of image filenames during the upload process. When users attempt to upload image files, the application does not adequately verify the actual file type or properly sanitize the filename before saving it to the server. This allows attackers to craft filenames that appear to be image files but contain malicious script content. The vulnerability manifests when the application saves these files with a .txt extension, which bypasses typical security measures that would prevent execution of script files. This behavior creates a scenario where attackers can upload potentially harmful files that remain undetected by standard security mechanisms.
The operational impact of this vulnerability is significant despite its limited usage scenarios. According to vendor assessment, while the attack surface may be constrained, the potential for exploitation exists in specific conditions. The vulnerability can be classified under CWE-434, which describes "Unrestricted Upload of File with Dangerous Type." This classification indicates that the vulnerability allows for unrestricted file uploads that could lead to arbitrary code execution or other security breaches. The security implications extend beyond simple file upload capabilities, as the vulnerability could enable attackers to gain unauthorized access to the web server, potentially leading to complete system compromise.
Mitigation strategies for CVE-2007-4913 should focus on implementing robust input validation and file type checking mechanisms. Organizations should ensure that all file uploads undergo strict validation based on content type rather than relying solely on filename extensions. The application should implement proper file extension filtering, MIME type verification, and file content analysis to prevent malicious files from being saved. Additionally, uploaded files should be stored in a location that is not directly accessible via the web server, and proper file permissions should be enforced to prevent execution of uploaded content. Security measures should also include implementing the principle of least privilege for file upload directories and monitoring upload activities for suspicious patterns. The ATT&CK framework categorizes this vulnerability under T1190, which describes "Exploit Public-Facing Application," emphasizing the need for proper application security controls and regular security assessments to prevent exploitation of such vulnerabilities.