CVE-2022-37426

What it actually does

The vulnerability permits unauthenticated or low-privileged upload of files with arbitrary extensions and content types through the OpenNebula core API or management interface, allowing injection of executable or malicious payloads directly into storage locations used by the platform.

Why it matters to the business

Successful exploitation can result in unauthorized modification of virtual machine images, templates, or configuration data, leading to loss of control over cloud workloads, potential lateral movement within the virtualization environment, and operational disruption of hosted services.

How an attack unfolds

An attacker identifies an exposed OpenNebula management endpoint and crafts a POST request containing a file with a dangerous type such as a script or executable; the core accepts and stores the file without type validation, enabling subsequent execution or use in further attacks against the infrastructure.

How to fix it

Apply the latest OpenNebula core release that enforces strict file-type allow-lists and content validation on all upload paths; until a patch is available, deploy network-level controls to restrict access to management interfaces and implement web application firewall rules that block uploads of executable MIME types and extensions.

How to confirm the fix worked

Review OpenNebula configuration and source code for the presence of file-type whitelist enforcement on all upload handlers; test by attempting to upload a disallowed file type from an unauthenticated context and confirm rejection; monitor release notes for security fixes addressing input validation.

Typical attack path

1. Discover publicly reachable OpenNebula management or API endpoint
2. Craft and submit an upload request with a file containing malicious content and a permitted but dangerous extension
3. Confirm storage of the injected file in a location accessible to the hypervisor or management processes
4. Trigger or reference the file to achieve code execution or configuration tampering

How to detect it

Examine web server and OpenNebula daemon logs for POST requests to upload endpoints that contain file names with executable extensions or unexpected MIME types; search for newly created files in storage directories that match suspicious patterns shortly after upload activity.

• POST requests to /rpc or management upload paths containing .php, .sh, .exe, or .jsp extensions
• Log entries showing file uploads accepted without content-type validation errors
• New files appearing in VM image or template directories with executable permissions

What your security team should do

• Immediately restrict network access to OpenNebula management ports to trusted administrative networks only
• Deploy or tune a web application firewall to enforce upload content-type and extension restrictions
• Audit all existing uploaded files for unexpected executable content or scripts
• Establish a process to apply OpenNebula security updates within 30 days of release