How to remediate – CCProxy Application Proxy Detection

1. Introduction

CCProxy Application Proxy Detection identifies instances where a host is running CCProxy in an open proxy configuration. This allows external users to potentially impersonate your network when connecting to outside services, and could be used as a relay for malicious activity like spamming. Systems affected are typically those running the CCProxy application on Windows platforms. Impact: Confidentiality – potential information disclosure; Integrity – potential data manipulation; Availability – possible service disruption due to misuse.

2. Technical Explanation

CCProxy is an application proxy that supports protocols like Telnet, FTP and WWW. When configured as an open proxy, it does not require authentication for external connections. This allows anyone on the internet to connect through your server. An attacker could use this to hide their source IP address or launch attacks against other systems. The vulnerability lies in misconfiguration rather than a software flaw.

• Root cause: CCProxy is configured without authentication, allowing unrestricted access.
• Exploit mechanism: An attacker connects to the open proxy and uses it as an intermediary for network requests. For example, they could use it to scan ports on other systems or send spam emails.
• Scope: Windows systems running CCProxy versions where open proxy functionality is enabled.

3. Detection and Assessment

You can confirm if a system is acting as an open proxy by checking its configuration settings and network connections. A quick check involves using `netstat` to identify listening ports, while thorough assessment requires examining the CCProxy application itself.

• Quick checks: Use netstat -an | find "808" or netstat -an | find "80" to check for CCProxy’s default ports (808 and 80).
• Scanning: Nessus plugin ID 34725 can detect open proxies. This is an example only, other scanners may also provide similar functionality.
• Logs and evidence: Check the CCProxy logs located in the installation directory for connections from unknown sources. The exact path varies depending on your configuration.

netstat -an | find "808"

4. Solution / Remediation Steps

The primary solution is to disable open proxy functionality in CCProxy if it’s not required, or configure authentication for all connections. These steps are small and testable.

4.1 Preparation

• Ensure you have administrator access to the system running CCProxy. A roll back plan involves restoring the backed-up configuration file and restarting the service.
• Change windows may be needed if this is a production server, requiring approval from IT management.

4.2 Implementation

1. Step 1: Open the CCProxy Configuration Console.
2. Step 2: Navigate to “Options” and then “General”.
3. Step 3: Disable the “Allow Internet Access” checkbox if it is enabled, or enable authentication under the “Authentication” tab.
4. Step 4: Restart the CCProxy service for changes to take effect.

4.3 Config or Code Example

Before

Allow Internet Access: Checked

After

Allow Internet Access: Unchecked

4.4 Security Practices Relevant to This Vulnerability

Several security practices can help prevent this issue. Least privilege reduces the impact if CCProxy is compromised, while secure defaults minimize misconfiguration risks.

• Practice 1: Least privilege – restrict access to the CCProxy configuration and service account.
• Practice 2: Secure Defaults – configure CCProxy with authentication enabled by default.

4.5 Automation (Optional)

Automation is not directly applicable for this vulnerability, as it requires manual configuration changes within the CCProxy console.

5. Verification / Validation

Confirm the fix by checking that external connections are no longer allowed through the proxy and verifying authentication is enabled if configured. A service smoke test involves confirming legitimate users can still access required resources.

• Post-fix check: Run netstat -an | find "808" again; it should return no results if the port is closed, or show connections only from trusted sources.
• Re-test: Re-run the quick check (Step 3) to confirm that CCProxy is no longer acting as an open proxy.
• Smoke test: Verify users can still access websites and applications through the proxy if authentication is enabled.
• Monitoring: Monitor CCProxy logs for failed connection attempts from unknown sources, indicating potential unauthorized access. This is an example only.

netstat -an | find "808"

6. Preventive Measures and Monitoring

Regular security baselines and policy updates can prevent this issue by enforcing secure CCProxy configurations. Implement checks in CI/CD pipelines to identify misconfigurations during deployment.

• Baselines: Update your security baseline or policy to require authentication for all CCProxy connections.
• Pipelines: Add a check in your CI/CD pipeline to verify that the “Allow Internet Access” checkbox is unchecked in CCProxy configurations.
• Asset and patch process: Review CCProxy configurations regularly as part of your asset management process, at least quarterly.

7. Risks, Side Effects, and Roll Back

Disabling open proxy functionality may disrupt legitimate users if they rely on it. Enabling authentication requires managing user accounts and passwords. A roll back involves restoring the backed-up configuration file and restarting the service.

• Risk or side effect 1: Disabling open proxy access could break existing applications that depend on it. Mitigate by testing changes in a non-production environment first.
• Risk or side effect 2: Enabling authentication adds administrative overhead for user management. Mitigate by using existing directory services if possible.
• Roll back: Restore the backed-up CCProxy configuration file and restart the service.

8. References and Resources

• Vendor advisory or bulletin: http://www.youngzsoft.net/ccproxy/