1. Introduction
FlexCMS Login Cookie SQL Injection is a vulnerability in the FlexCMS content management system that allows attackers to inject malicious SQL code into database queries via the ‘FCLoginData12345’ cookie. This can lead to unauthorized access to sensitive information, data modification, or attacks against the underlying database server. Systems running vulnerable versions of FlexCMS are at risk. A successful exploit could compromise confidentiality, integrity and availability of the system.
2. Technical Explanation
The vulnerability occurs because FlexCMS fails to properly sanitize user input received in the ‘FCLoginData12345’ login cookie when constructing database queries. If PHP’s ‘magic_quotes_gpc’ setting is disabled, an attacker can inject SQL commands into this cookie, altering the query logic and potentially gaining control of the database.
- Exploit mechanism: An attacker crafts a malicious SQL injection payload within the ‘FCLoginData12345’ cookie, which is then executed by the FlexCMS application when processing the login request. For example, an attacker could inject code to bypass authentication or retrieve sensitive data from other tables.
- Scope: FlexCMS versions prior to 2.6 are known to be affected.
3. Detection and Assessment
To confirm vulnerability, check the installed FlexCMS version and review application logs for suspicious database activity.
- Quick checks: Check the FlexCMS version in the admin interface or by examining the file structure for version information.
- Scanning: Nessus plugin ID 36179 can detect this vulnerability. Other scanners may also have relevant signatures.
- Logs and evidence: Monitor database logs for unusual queries, particularly those containing characters commonly used in SQL injection attacks (e.g., single quotes, double quotes, semicolons). Look for errors related to invalid SQL syntax.
# Example command placeholder:
# No specific command available without access to the server environment. Review logs as described above.
4. Solution / Remediation Steps
Currently, there is no known official solution for this vulnerability. Mitigation steps should focus on preventing exploitation until a patch is released.
4.1 Preparation
- Ensure you have access to restore the backup in case of issues. A roll back plan involves restoring the original backups.
- A change window may be required depending on your environment. Approval from a security team is recommended.
4.2 Implementation
- Step 1: Disable or remove the ‘FCLoginData12345’ cookie if possible, and implement alternative authentication methods that do not rely on cookies for sensitive data.
- Step 2: Implement a Web Application Firewall (WAF) with SQL injection protection rules to block malicious requests targeting the login endpoint.
- Step 3: Regularly monitor application logs for suspicious activity and review security configurations.
4.3 Config or Code Example
Before
# No specific code example available as the vulnerability lies within the FlexCMS application logic. The insecure code handles the 'FCLoginData12345' cookie without proper sanitization.
After
# Implement WAF rules to block SQL injection attempts targeting the login endpoint. Example (may vary depending on your WAF):
# Rule: Block requests containing suspicious SQL keywords in the 'FCLoginData12345' cookie.
4.4 Security Practices Relevant to This Vulnerability
- Practice 1: Implement robust input validation on all user-supplied data, including cookies, POST parameters, and GET requests.
- Practice 2: Apply the principle of least privilege to database accounts used by FlexCMS, limiting their access to only the necessary tables and operations.
4.5 Automation (Optional)
No specific automation script is available for this vulnerability due to the lack of a patch. However, WAF rules can be automated using configuration management tools.
# Example Ansible snippet to configure WAF rule:
# - name: Add SQL injection protection rule to WAF
# ansible.builtin.command: waf-cli add_rule --name "FlexCMS SQL Injection" --pattern "/login endpoint with FCLoginData12345 cookie" --action "block"
5. Verification / Validation
- Post-fix check: Attempt a login with a crafted payload in the ‘FCLoginData12345’ cookie. The request should be blocked by the WAF, and no errors related to SQL syntax should appear in the logs.
- Re-test: Re-run the earlier detection methods (e.g., Nessus scan) to confirm that the vulnerability is no longer detected.
- Monitoring: Monitor database logs for any unusual queries or errors related to SQL injection attempts.
# Post-fix command and expected output:
# Attempt login with payload 'test' OR 1=1 --'. Expected result: WAF blocks the request, and no successful login occurs.
6. Preventive Measures and Monitoring
- Baselines: Update your security baseline or policy to require robust input validation on all user-supplied data, including cookies.
- Pipelines: Add Static Application Security Testing (SAST) tools to your CI pipeline to identify potential SQL injection vulnerabilities in the FlexCMS code base.
- Asset and patch process: Establish a regular patch review cycle for FlexCMS and other web applications to ensure timely updates and fixes for known vulnerabilities.
7. Risks, Side Effects, and Roll Back
Implementing WAF rules may cause false positives, blocking legitimate requests. Disabling the ‘FCLoginData12345’ cookie could break existing functionality. Roll back involves removing the WAF rule or re-enabling the cookie.
- Risk or side effect 1: False positives from WAF rules. Mitigation: Fine-tune WAF rules to minimize false positives while maintaining effective protection.
- Roll back: Step 1: Remove the WAF rule blocking SQL injection attempts. Step 2: Re-enable the ‘FCLoginData12345’ cookie if it was disabled.