1. Introduction
Ivanti Connect Secure is a VPN solution affected by a command injection vulnerability. This allows an unauthenticated attacker to execute arbitrary commands on the appliance, potentially compromising its confidentiality, integrity and availability. Systems running Ivanti Connect Secure 9.x or 22.x are usually affected.
2. Technical Explanation
The Ivanti Connect Secure web components (versions 9.x and 22.x) contain a command injection vulnerability due to insufficient input validation. An attacker can send specially crafted requests to the appliance, which are then processed without proper sanitisation, leading to arbitrary command execution. This vulnerability is tracked as CVE-2024-21887. A realistic example involves sending a malicious payload through an HTTP request that injects commands into the system’s shell.
- Root cause: Missing input validation in web components allows for arbitrary command execution.
- Exploit mechanism: An unauthenticated attacker sends crafted requests to execute commands on the appliance. For example, injecting a command within an HTTP parameter that is then executed by the system.
- Scope: Ivanti Connect Secure versions 9.x and 22.x are affected.
3. Detection and Assessment
To confirm vulnerability, check the installed version of Ivanti Connect Secure. A thorough method involves reviewing web server logs for suspicious requests.
- Quick checks: Use the command line interface to display the software version.
- Scanning: Nessus plugin ID 11330e19 can detect this vulnerability, but results should be verified.
- Logs and evidence: Review Ivanti Connect Secure web server logs for unusual requests containing shell metacharacters or commands.
4. Solution / Remediation Steps
4.1 Preparation
- Ensure you have a rollback plan in place, including restoring from backup. A change window is recommended with approval from security and network teams.
4.2 Implementation
- Step 1: Download the latest patch for Ivanti Connect Secure from the vendor’s website.
- Step 2: Install the downloaded patch on the affected appliance.
4.3 Config or Code Example
Before
After
4.4 Security Practices Relevant to This Vulnerability
Implement least privilege and input validation to reduce the impact of potential exploits. A regular patch cadence is also crucial for addressing vulnerabilities promptly.
- Practice 1: Least privilege reduces the scope of damage if an attacker gains access.
- Practice 2: Input validation prevents malicious commands from being executed by filtering or sanitising user input.
4.5 Automation (Optional)
5. Verification / Validation
Confirm the patch installation by checking the software version. Re-run earlier detection methods to verify the vulnerability is no longer present. Perform basic service smoke tests to ensure functionality remains intact.
- Post-fix check: Use the command line interface to confirm the installed version is updated and includes the security fix.
- Re-test: Run Nessus plugin ID 11330e19 again; it should no longer report the vulnerability.
- Monitoring: Monitor Ivanti Connect Secure logs for any suspicious activity or errors related to command execution.
6. Preventive Measures and Monitoring
Update security baselines to include the latest patch levels for Ivanti Connect Secure. Implement regular vulnerability scanning in CI/CD pipelines to identify similar issues early on. Maintain a sensible patch review cycle based on risk assessment.
- Baselines: Update your security baseline or policy to require the latest Ivanti Connect Secure version with the fix applied.
- Pipelines: Add vulnerability scanning tools to your CI/CD pipeline to detect similar vulnerabilities during development and deployment.
- Asset and patch process: Review and apply patches for Ivanti Connect Secure on a regular basis, ideally within 72 hours of release.
7. Risks, Side Effects, and Roll Back
Patching may cause temporary service disruption. Ensure you have a rollback plan in place to restore the previous configuration if needed.
- Risk or side effect 1: Patch installation could temporarily interrupt VPN connectivity.
- Risk or side effect 2: In rare cases, patching might introduce compatibility issues with other systems.
- Roll back: Restore the Ivanti Connect Secure appliance from the pre-patch backup if any issues occur.
8. References and Resources
- Vendor advisory or bulletin: http://www.nessus.org/u?11330e19
- NVD or CVE entry: CVE-2024-21887
- Product or platform documentation relevant to the fix: No specific link available.