NeuVector Enforcer is vulnerable to Command Injection and Buffer overflow

QFinch assessment

A vulnerability was identified in NeuVector, where the enforcer used environment variables `CLUSTER_RPC_PORT` and `CLUSTER_LAN_PORT` to generate a command to be executed via `popen`, without first sanitising their values.

Potential impact

A vulnerability was identified in NeuVector, where the enforcer used environment variables CLUSTERRPCPORT and CLUSTERLANPORT to generate a command to be executed via popen, without first sanitising their values. The entry process of the enforcer container is the monitor process. When the enforcer container stops, the monitor process checks whether the consul subprocess has exited. To perform this check, the monitor process uses the popen function to execute a shell command that determines whether the ports used by the consul subprocess are still active. The values of environment variables CLUSTERRPCPORT and CLUSTERLANPORT are used directly to compose shell commands via popen without validation or sanitization. This behavior could allow a malicious user to inject malicious commands through these variables within the enforcer container. In the patched version, the monitor process validates the values of CLUSTERRPCPORT and CLUSTERLANPORT to ensure they contain only valid port numbers before invoking the popen command. If validation fails, the monitor process exits immediately, causing the enforcer container to terminate. This prevents the execution of any injected or malicious commands.