Stenographer¶

From https://github.com/google/stenographer:

Stenographer is a full-packet-capture utility for buffering packets to disk for intrusion detection and incident response purposes. It provides a high-performance implementation of NIC-to-disk packet writing, handles deleting those files as disk fills up, and provides methods for reading back specific sets of packets quickly and easily.

Stenographer uses AF-PACKET for packet acquisition.

Output¶

Stenographer writes full packet capture to /nsm/pcap/. It will automatically start purging old data once the partition reaches 90%.

Analysis¶

You can access full packet capture via PCAP:

Alerts, Hunt, and Kibana allow you to easily pivot to the PCAP page.

Alternatively, you can access packet capture from the command line using stenoread and a steno query as defined at https://github.com/google/stenographer#querying. In the following example, replace “YourStenoQueryHere” with your actual steno query:

sudo docker exec -it so-steno stenoread "YourStenoQueryHere" -w /tmp/new.pcap

You can then find the resulting pcap file in /nsm/pcaptmp/ in the host filesystem.

Configuration¶

Stenographer reads its configuration from /opt/so/conf/steno/. However, please keep in mind that if you make any changes to this directory they may be overwritten since the configuration is managed with Salt.

Diagnostic Logging¶

Diagnostic logging for Stenographer can be found at /opt/so/log/stenographer/.

Disabling¶

If you need to disable Stenographer, you can set the Salt pillar steno:enabled:false in the global.sls or in the sensor’s minion.sls file.