CVE-2016-9956

What it actually does

The route manager component in FlightGear accepts untrusted Nasal scripts over the network and fails to sanitize file paths, enabling arbitrary file writes on the host filesystem.

Why it matters to the business

Attackers could corrupt or overwrite configuration, data, or system files on any machine running the vulnerable flight simulator, leading to loss of integrity, potential follow-on compromise, and operational disruption for users or organizations relying on the software.

How an attack unfolds

An attacker crafts a malicious Nasal script containing a path traversal sequence and sends it to the exposed route manager service; the unsanitized path causes the script to write attacker-controlled content to any location on disk.

How to fix it

Upgrade FlightGear to version 2016.4.4 or later on all affected systems; if an upgrade is not immediately possible, restrict network access to the route manager and disable untrusted Nasal script execution.

How to confirm the fix worked

Confirm the installed FlightGear version is 2016.4.4 or newer; review Nasal script handling code for path sanitization and test with known traversal payloads in a lab environment.

Typical attack path

1. Identify a reachable FlightGear instance exposing the route manager
2. Craft a Nasal script that uses path traversal to target a writable file
3. Transmit the script to the route manager
4. Achieve arbitrary file write on the host

How to detect it

Search application and system logs for unexpected file writes originating from Nasal script execution; look for anomalous file paths containing traversal sequences in process or audit logs.

What your security team should do

• Prioritize patching FlightGear to 2016.4.4+ across all environments
• Block inbound access to the route manager port from untrusted networks
• Monitor for any remaining instances of FlightGear older than 2016.4.4