How to remediate – ArGoSoft Mail Server HTTP Daemon GET Request Saturation DoS

1. Introduction

ArGoSoft Mail Server HTTP Daemon GET Request Saturation DoS is a denial-of-service vulnerability affecting ArGoSoft Mail Server. An attacker can crash the mail server by sending an invalid request to its HTTP daemon. This impacts availability of email services. Affected systems are typically those running ArGoSoft Mail Server with the HTTP daemon enabled.

2. Technical Explanation

The vulnerability occurs because the ArGoSoft Mail Server HTTP daemon does not properly handle malformed or excessively large GET requests. An unauthenticated attacker can send a specially crafted request that exhausts server resources, leading to a crash.

• Root cause: Insufficient input validation on HTTP GET requests allows for resource exhaustion.
• Exploit mechanism: An attacker sends an invalid or oversized HTTP GET request to the mail server’s HTTP daemon.
• Scope: ArGoSoft Mail Server with the HTTP daemon enabled is affected. Specific versions are not detailed in available information.

3. Detection and Assessment

Confirming vulnerability requires checking if the HTTP daemon is running and accessible, then testing its resilience to malformed requests.

• Quick checks: Use netstat -an | grep 80 or telnet 80 to check if port 80 (or the configured HTTP port) is listening.
• Scanning: Nessus plugin ID 7873 may detect this vulnerability, but results should be verified manually.
• Logs and evidence: Check ArGoSoft Mail Server logs for errors related to HTTP request processing or daemon crashes. Specific log paths depend on the server configuration.

telnet  80

4. Solution / Remediation Steps

Currently, there is no known official solution for this vulnerability. Mitigation focuses on limiting exposure and monitoring for crashes.

4.1 Preparation

• Stopping the HTTP daemon will prevent exploitation but also disable webmail access. A roll back plan involves restarting the service.

4.2 Implementation

1. Step 1: If webmail functionality is not required, stop the ArGoSoft Mail Server HTTP daemon. The method varies depending on the operating system and installation type.
2. Step 2: Monitor server logs for any unexpected crashes or errors related to HTTP requests.

4.3 Config or Code Example

There is no configuration change available as there is no known patch.

Before

After

4.4 Security Practices Relevant to This Vulnerability

Practices that reduce the attack surface and improve monitoring are relevant here.

• Least privilege: Limit access to the mail server and its components to only authorized users and services.
• Monitoring: Implement robust logging and alerting for unexpected crashes or errors.

4.5 Automation (Optional)

No automation is available given the lack of a patch.

5. Verification / Validation

• Post-fix check: Use netstat -an | grep 80 or attempt a connection via telnet 80; it should fail if the daemon is stopped.
• Re-test: Attempt to send a malformed HTTP GET request (e.g., very long URL) and verify that the server does not crash.
• Smoke test: If the HTTP daemon remains running, ensure basic email functionality (sending/receiving) still works as expected.
• Monitoring: Monitor ArGoSoft Mail Server logs for errors related to HTTP request processing or daemon crashes.

telnet  80

6. Preventive Measures and Monitoring

Regular security assessments, patch management (when available), and monitoring are key preventive measures.

• Baselines: Implement a baseline configuration for ArGoSoft Mail Server that includes disabling unnecessary services like the HTTP daemon if not used.
• Pipelines: If custom scripts or configurations manage ArGoSoft Mail Server, include checks to ensure secure settings are applied.
• Asset and patch process: Regularly review security advisories and apply patches promptly when available.

7. Risks, Side Effects, and Roll Back

Stopping the HTTP daemon disables webmail access. Re-enabling it restores functionality but reintroduces the vulnerability until a patch is applied.

• Risk or side effect 1: Disabling the HTTP daemon prevents users from accessing webmail.
• Roll back: Restart the ArGoSoft Mail Server HTTP daemon to restore webmail access. The method varies depending on the operating system and installation type.

8. References and Resources

Links to relevant vulnerability information.

• Vendor advisory or bulletin: No official advisory is currently available.
• NVD or CVE entry: No CVE entry is currently assigned for this vulnerability.
• Product or platform documentation relevant to the fix: https://www.securityfocus.com/archive/1/324750