How to remediate – Ivanti Connect Secure 9.x / 22.x SSRF (CVE-2024-21893)

1. Introduction

Ivanti Connect Secure is a VPN solution affected by a server-side request forgery (SSRF) vulnerability, CVE-2024-21893. This allows an unauthenticated attacker to send malicious requests through the vulnerable server, potentially accessing internal systems or data. Systems running Ivanti Connect Secure versions 9.x and 22.x are affected. Successful exploitation could lead to confidentiality, integrity, and availability compromise of connected resources.

2. Technical Explanation

The vulnerability exists in the web components of Ivanti Connect Secure 9.x and 22.x due to insufficient input validation when handling user-supplied data. An attacker can craft a request that causes the server to make connections to arbitrary internal or external systems, bypassing firewall restrictions. The CVSS score is currently unconfirmed but considered High severity.

• Root cause: Missing input validation in web component requests allows manipulation of outbound network connections.
• Exploit mechanism: An attacker sends a specially crafted HTTP request to the Ivanti Connect Secure server, containing parameters that specify an untrusted destination system. The server then makes a connection to this specified system on behalf of the attacker. For example, an attacker could attempt to connect to an internal database server.
• Scope: Ivanti Connect Secure versions 9.x and 22.x are affected.

3. Detection and Assessment

To confirm vulnerability, first check the installed version of Ivanti Connect Secure. Thorough assessment involves reviewing web access logs for suspicious outbound connections.

• Quick checks: Use the Ivanti Connect Secure administration interface to determine the software version.
• Scanning: Nessus plugin ID 174658 can detect this vulnerability, but results should be verified manually.
• Logs and evidence: Examine web access logs for unusual outbound connections originating from the Ivanti Connect Secure server. Look for requests to internal IP addresses or unexpected external domains.

# Example command placeholder (check version via CLI - specific commands depend on OS/Ivanti configuration)
# ivanticsc --version 

4. Solution / Remediation Steps

Apply the vendor-supplied patch or upgrade to a fixed version of Ivanti Connect Secure. Follow these steps carefully to minimize service disruption.

4.1 Preparation

• Stop the Ivanti Connect Secure service prior to patching or upgrading. A roll back plan involves restoring the previous configuration and restarting the service.
• A change window may be required, depending on your organization’s policies. Approval from the security team is recommended.

4.2 Implementation

1. Step 1: Download the latest patch or upgrade package from the Ivanti support portal.
2. Step 2: Stop the Ivanti Connect Secure service.
3. Step 3: Install the downloaded patch or upgrade package following the vendor’s instructions.
4. Step 4: Restart the Ivanti Connect Secure service.

4.3 Config or Code Example

Before

# No specific configuration example available, as the vulnerability is in the application code itself. Ensure you are running a patched version.

After

# Verify the installed version after patching:
# ivanticsc --version 
# Expected output should show a version greater than or equal to the fixed version specified by Ivanti.

4.4 Security Practices Relevant to This Vulnerability

Several security practices can mitigate this type of vulnerability. Least privilege reduces impact if exploited, and input validation prevents unsafe data from reaching the server. A robust patch cadence ensures timely application of security updates.

• Practice 1: Implement least privilege principles for all services to limit potential damage from successful exploits.
• Practice 2: Enforce strict input validation on all user-supplied data to prevent malicious requests.

4.5 Automation (Optional)

# Example PowerShell script for automated patching (requires Ivanti patch management integration):
# Invoke-IvantiPatch -PatchID {Patch ID from Ivanti} -TargetServers {Server List}
# Note: This is a placeholder and requires specific configuration based on your environment.

5. Verification / Validation

• Post-fix check: Run `ivanticsc –version` and verify that the output shows a patched version as specified by Ivanti’s advisory.
• Re-test: Re-run the Nessus scan (ID 174658) to confirm it no longer detects the vulnerability.
• Monitoring: Monitor web access logs for any unusual outbound connections originating from the Ivanti Connect Secure server as an example of regression detection.

# Post-fix command and expected output (example):
# ivanticsc --version 
# Output: Ivanti Connect Secure version X.Y.Z (patched)

6. Preventive Measures and Monitoring

Update security baselines to include patched versions of Ivanti Connect Secure. Incorporate vulnerability scanning into CI/CD pipelines to identify similar issues early in the development lifecycle. Implement a regular patch review cycle that fits your organization’s risk tolerance.

• Baselines: Update security configuration baselines (e.g., CIS benchmarks) to require patched versions of Ivanti Connect Secure.
• Pipelines: Add vulnerability scanning tools (SAST, DAST) to CI/CD pipelines to detect similar vulnerabilities in code and configurations.
• Asset and patch process: Establish a regular patch review cycle (e.g., weekly or monthly) to ensure timely application of security updates.

7. Risks, Side Effects, and Roll Back

• Risk or side effect 1: Patching could temporarily interrupt VPN connectivity. Schedule maintenance during off-peak hours to minimize impact.
• Roll back:
  1. Stop the Ivanti Connect Secure service.
  2. Restore the previous configuration from backup.
  3. Restart the Ivanti Connect Secure service.

8. References and Resources

• Vendor advisory or bulletin: https://www.ivanti.com/security-advisories
• NVD or CVE entry: https://nvd.nist.gov/vuln/detail/CVE-2024-21893
• Product or