CVE-2018-18965 in osCommerce
Summary
by MITRE
osCommerce 2.3.4.1 has an incomplete '.htaccess' for blacklist filtering in the "product" page. The .htaccess file in catalog/images/ bans the html extension, but there are several alternative cases in which HTML can be executed, such as a file with no extension or an unrecognized extension (e.g., the test or test.asdf filename).
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Analysis
by VulDB Data Team • 06/04/2023
The vulnerability identified as CVE-2018-18965 affects osCommerce version 2.3.4.1 and represents a critical access control flaw stemming from inadequate .htaccess configuration in the product page functionality. This issue resides within the catalog/images/ directory where the security mechanism fails to provide comprehensive protection against unauthorized HTML execution. The primary .htaccess file implements a blacklist filtering approach that specifically blocks files with the .html extension, yet this restrictive measure proves insufficient as attackers can exploit alternative file naming conventions to bypass the protection mechanisms. The vulnerability demonstrates a fundamental misunderstanding of secure access control implementation where a single point of failure exists in the filtering logic.
The technical flaw manifests through the incomplete blacklist implementation that relies on specific file extension blocking rather than comprehensive security controls. When a file lacks an extension or possesses an unrecognized extension such as test or test.asdf, the existing .htaccess rules fail to prevent execution of potentially malicious HTML content. This oversight creates a pathway for attackers to upload or place files that could execute HTML code within the web application context. The vulnerability operates under CWE-116 which categorizes improper encoding or escaping of output, and more specifically relates to CWE-623 where insufficient filtering allows malicious content to be executed. The incomplete blacklist approach represents a classic security by obscurity pattern that fails to account for all possible attack vectors.
The operational impact of this vulnerability extends beyond simple privilege escalation as it enables arbitrary code execution within the web application environment. An attacker who can upload files to the catalog/images/ directory can leverage this flaw to execute malicious HTML content that may include cross-site scripting payloads, malicious redirects, or other harmful code. The vulnerability affects the application's integrity and availability, potentially allowing attackers to compromise the entire web application infrastructure. This issue directly maps to attack techniques described in the ATT&CK framework under T1059.005 for command and scripting interpreter and T1203 for Exploitation for Client Execution, as the vulnerability enables unauthorized execution of code through web-based interfaces.
Mitigation strategies for CVE-2018-18965 require comprehensive implementation of both whitelist and blacklist security controls to prevent unauthorized file execution. Organizations should implement strict file extension validation that prevents upload of any file without proper extensions or with potentially dangerous extensions such as .php, .asp, .jsp, or .html. The .htaccess configuration must be enhanced to include comprehensive extension filtering that covers all possible file naming conventions and ensures that files without proper extensions cannot be executed. Security measures should also include regular monitoring of uploaded files, implementation of proper file type validation at the application level, and consideration of using a whitelist approach that explicitly allows only known safe file types rather than relying on blacklist filtering. Additionally, the web application should be configured to treat all uploaded files as potentially malicious until proven otherwise, and proper input sanitization should be implemented to prevent any bypass attempts through encoding or alternative naming conventions.