Impact

An attacker with the ability to establish a streaming connection can execute arbitrary commands on the targeted Netdata agent.

When an alert is triggered, the function health_alarm_execute is called. This function performs different checks and then enqueues a command by calling spawn_enq_cmd. This command is populated with several arguments that are not sanitized. One of them is the registry_hostname of the node for which the alert is raised. By providing a specially crafted registry_hostname as part of the health data that is streamed to a Netdata (parent) agent, an attacker can execute arbitrary commands at the remote host as a side-effect of the raised alert.

Note that the commands are executed as the user running the Netdata Agent. This user is usually named netdata. The ability to run arbitrary commands may allow an attacker to escalate privileges by escalating other vulnerabilities in the system, as that user.

Patches

The problem has been fixed in:

Netdata agent v1.37 (stable)
Netdata agent v1.36.0-409 (nightly)

Workarounds

Streaming is not enabled by default. If you have previously enabled this, it can be disabled by modifying stream.conf:

[stream]
    enabled = no

Limiting access to the port on the recipient Agent to trusted child connections may mitigate the impact of this vulnerability.

References

• Documentation on streaming and replication

For more information

If you have any questions or comments about this advisory:

• Open an issue in netdata/netdata
• Email us at security@netdata.cloud