CVE-2005-3975 in Drupal
Summary
by MITRE
Interpretation conflict in file.inc in Drupal 4.5.0 through 4.5.5 and 4.6.0 through 4.6.3 allows remote authenticated users to inject arbitrary web script or HTML via HTML in a file with a GIF or JPEG file extension, which causes the HTML to be executed by a victim who views the file in Internet Explorer as a result of CVE-2005-3312. NOTE: it could be argued that this vulnerability is due to a design flaw in Internet Explorer and the proper fix should be in that browser; if so, then this should not be treated as a vulnerability in Drupal.
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Analysis
by VulDB Data Team • 07/06/2021
The vulnerability described in CVE-2005-3975 represents a complex interpretation conflict within Drupal's file handling mechanism that exploits a fundamental mismatch between how different web browsers process file content. This issue affects Drupal versions 4.5.0 through 4.5.5 and 4.6.0 through 4.6.3, where the system fails to properly validate file extensions and content types when processing uploaded files. The flaw specifically manifests when users upload files with .gif or .jpeg extensions but containing HTML or script content, creating a scenario where the server's file interpretation logic conflicts with browser rendering behavior.
The technical exploitation occurs through a sophisticated attack vector that leverages CVE-2005-3312, which was a critical vulnerability in Internet Explorer's handling of mixed content types. When a user uploads a file with a graphics extension but containing embedded HTML or JavaScript code, Drupal's file.inc component processes the file based on its extension rather than its actual content. This creates a dangerous situation where the server accepts the file as a legitimate image but fails to sanitize the embedded content properly. The vulnerability stems from a fundamental design flaw in how Drupal handles file type validation, which operates under the assumption that file extensions accurately represent content type, a dangerous assumption that modern security practices strongly discourage.
The operational impact of this vulnerability extends beyond simple cross-site scripting attacks to potentially enable more sophisticated exploitation techniques. Attackers can craft malicious files that appear harmless as images but contain embedded scripts that execute when viewed in Internet Explorer, which was particularly vulnerable due to its permissive handling of mixed content. This creates a chain reaction where the initial file upload bypasses Drupal's security controls, and the subsequent browser rendering process executes malicious code in the context of the victim's session. The vulnerability demonstrates how application-level flaws can compound browser-level weaknesses to create dangerous attack scenarios, with implications for user data integrity and session security.
The security implications of this vulnerability align with CWE-79, which describes cross-site scripting vulnerabilities that occur when untrusted data is sent to a web browser without proper validation or sanitization. This classification emphasizes the fundamental nature of the flaw as a failure to properly validate and sanitize user input, particularly in file handling contexts. The attack scenario also intersects with ATT&CK technique T1059, which covers command and scripting interpreter usage, as the malicious scripts embedded in these files can execute within the victim's browser environment. Organizations using affected Drupal versions faced significant risk of credential theft, session hijacking, and data exfiltration attacks that could compromise entire user bases through seemingly benign file uploads.
The suggested mitigations for this vulnerability require a multi-layered approach that addresses both the application-level flaw and the browser-level weakness. Immediate fixes should involve implementing strict content validation that examines actual file content rather than relying solely on file extensions, with proper sanitization of any embedded HTML or script content. Organizations should also implement robust file type checking mechanisms that verify file signatures and content types against expected formats, rather than trusting extension-based identification. Additionally, users should be educated about the risks of viewing potentially malicious files, and administrators should consider implementing additional security controls such as content security policies and web application firewalls. The vulnerability ultimately underscores the importance of defense-in-depth strategies and the necessity of treating file upload validation as a critical security control rather than a simple convenience feature.