How to remediate – php-Charts Detection

1. Introduction

php-Charts Detection identifies a chart creation application hosted on your web server. php-Charts is a PHP tool used for generating images from data, and its presence indicates a potential attack surface if not properly managed. A successful exploit could lead to information disclosure or remote code execution. Confidentiality, integrity, and availability may be impacted.

2. Technical Explanation

The vulnerability arises from hosting the php-Charts application on a publicly accessible web server without appropriate security measures. An attacker can send crafted requests to the application to potentially execute arbitrary PHP code or access sensitive data. There is no known CVE associated with simply *hosting* the application, but exploitation of vulnerabilities within php-Charts itself are possible.

• Root cause: The presence of a publicly accessible php-Charts installation without sufficient security controls.
• Exploit mechanism: An attacker could submit malicious input through the chart creation interface or directly access vulnerable scripts within the application to execute code on the server. For example, an attacker might attempt to upload and execute a PHP shell script via a chart image parameter.
• Scope: Web servers running PHP with a publicly accessible php-Charts installation are affected. Specific versions depend on known vulnerabilities in the php-Charts code itself; older versions are more likely to be vulnerable.

3. Detection and Assessment

Confirming the presence of php-Charts is the first step. You can check for specific files or access the application through a web browser.

• Quick checks: Browse to the web server’s document root and look for directories named ‘phpcharts’ or files with extensions like ‘.php’ containing ‘chart’.
• Scanning: Nessus plugin ID 163842 may identify php-Charts installations. This is an example only, and results should be verified manually.
• Logs and evidence: Web server access logs might show requests to URLs containing ‘/phpcharts/’ or filenames associated with the application.

ls -l /var/www/html/phpcharts

4. Solution / Remediation Steps

The best solution is typically to remove php-Charts if it’s not actively required. If needed, ensure it’s properly secured.

4.1 Preparation

• Ensure you have access to restore the backup if needed. A roll back plan involves restoring the original files and restarting the web service.
• Changes should be approved by a senior IT administrator.

4.2 Implementation

1. Step 1: Remove the php-Charts directory from the web server’s document root using the command line or file manager. For example, `rm -rf /var/www/html/phpcharts`.
2. Step 2: Clear any associated caches (e.g., opcode cache, browser cache).
3. Step 3: Restart the web service to apply the changes. For example, `systemctl restart apache2` or `systemctl restart nginx`.

4.3 Config or Code Example

This vulnerability doesn’t involve a specific configuration; it’s about removing unnecessary files.

Before

/var/www/html/phpcharts/ - Contains php-Charts application files

After

No /var/www/html/phpcharts directory present.

4.4 Security Practices Relevant to This Vulnerability

Several security practices can help prevent this issue.

• Practice 1: Least privilege – only install software that is absolutely necessary for the web server’s function.

4.5 Automation (Optional)

Ansible can automate file removal.

---
- name: Remove php-Charts directory
  file:
    path: /var/www/html/phpcharts
    state: absent
  become: true

5. Verification / Validation

Confirm the removal of php-Charts and verify that the web server functions as expected.

• Post-fix check: Run `ls -l /var/www/html` and confirm that no ‘phpcharts’ directory exists.
• Re-test: Repeat the quick checks from Section 3 to ensure php-Charts is no longer present.
• Smoke test: Access other web applications hosted on the server to verify they are still functioning correctly.
• Monitoring: Check web server access logs for any errors related to missing files or scripts that might have been part of the php-Charts installation.

ls -l /var/www/html

6. Preventive Measures and Monitoring

Proactive measures can reduce the risk of similar issues.

• Baselines: Update security baselines to include a list of approved software packages for web servers.
• Pipelines: Implement automated scanning in CI/CD pipelines to detect unused or vulnerable applications during deployment.
• Asset and patch process: Conduct regular asset inventories to identify and remove unnecessary software.

7. Risks, Side Effects, and Roll Back

Removing php-Charts could disrupt functionality if it’s still in use.

• Roll back: Restore the backup of the web server’s document root taken in Step 4.1. Restart the web service.

8. References and Resources

Information about php-Charts is available on its official website.

• Vendor advisory or bulletin: http://www.php-charts.com/
• NVD or CVE entry: Not applicable, as this relates to hosting the application itself.
• Product or platform documentation relevant to the fix: http://www.php-charts.com/documentation