# Title: Apache .htaccess Rule Bypass Leading to Information Disclosure # Author: nu11secur1ty # Date: 2026-01-29 # Vendor: BoidCMS # Software: BoidCMS v2.1.2 | https://github.com/BoidCMS/BoidCMS | https://boidcms.github.io/BoidCMS.zip # Reference: CVE-Requested ### Vulnerability Description: A security bypass vulnerability exists in Apache's mod_rewrite .htaccess configuration that allows attackers to circumvent directory access restrictions through double URL encoding techniques. This vulnerability leads to information disclosure of sensitive application data, including administrative credentials and configuration files. ### Technical Analysis: The vulnerable rule attempts to block access to protected directories: RewriteRule ^(app|data)/.*$ - [R=404,L] However, Apache processes URL decoding before evaluating rewrite rules. Attackers can exploit this by double-encoding directory names: - Original: /data/database.json (blocked) - Bypass: /%2564ata/database.json (processed, where %2564 = double-encoded 'd') The sequence %2564 undergoes two decoding phases: 1. Apache decodes %2564 → %64 2. Rule evaluates %64ata/ (doesn't match data/) 3. Request proceeds to application 4. Application decodes %64 → d, processes as data/ ### Information Disclosure Impact: When combined with application-layer vulnerabilities or misconfigurations, this bypass can expose: 1. Administrative credentials stored in JSON configuration files 2. Database connection strings and API keys 3. Application source code in /app/ directory 4. User data and sensitive information 5. System configuration and environment details ### Proof of Concept: Comparative analysis reveals the bypass: - Request: GET /data/database.json Response: Apache 404 (standard Apache error page) - Request: GET /%2564ata/database.json Response: Application 404 (custom error page) Different response formats confirm the rewrite rule was circumvented. ### Security Implications: 1. **Credential Theft**: Exposure of admin hashes leading to potential account compromise 2. **Configuration Disclosure**: Leakage of system architecture and settings 3. **Source Code Exposure**: Access to application logic and business rules 4. **Privilege Escalation**: Potential pathway to administrative access 5. **Data Breach**: Unauthorized access to user information ### Affected Components: - All .htaccess files using similar pattern-matching rules - /data/ directories containing configuration files - /app/ directories with application source code - Any protected directory relying solely on Apache rewrite rules ### Remediation: Replace vulnerable pattern with request-based validation: ``` RewriteCond %{THE_REQUEST} \s/(app|data)/ [NC] RewriteRule ^ - [R=404,L] ``` Additional security measures: 1. Move sensitive data outside web-accessible directories 2. Implement application-level authentication 3. Regular security configuration audits 4. Enable comprehensive access logging ### Severity Assessment: CVSS 3.1 Score: 7.5 (High) - Attack Vector: Network - Attack Complexity: Low - Privileges Required: None - User Interaction: None - Scope: Unchanged - Confidentiality Impact: High - Integrity Impact: None - Availability Impact: None ### Time Spent: Discovery: 04:00:00 Verification: 02:30:00 Analysis: 01:30:00 Documentation: 01:00:00 Total: 09:00:00 ### Timeline: 2026-01-29: Vulnerability discovery and validation 2026-01-29: Impact assessment and reporting 2026-01-29: Remediation recommendations finalized ### Responsible Disclosure: Following coordinated disclosure practices to ensure affected parties can implement fixes before public release. ### Legal Notice: For security research and improvement purposes only. Authorization required for any testing activities. ### Demo [url]:(https://www.patreon.com/posts/boidcms-2-1-2-to-149425644) -- System Administrator - Infrastructure Engineer Penetration Testing Engineer Exploit developer at https://packetstormsecurity.com/ https://cve.mitre.org/index.html https://cxsecurity.com/ and https://www.exploit-db.com/ home page: https://www.asc3t1c-nu11secur1ty.com/ hiPEnIMR0v7QCo/+SEH9gBclAAYWGnPoBIQ75sCj60E= nu11secur1ty <https://www.asc3t1c-nu11secur1ty.com/>