Updating Emerging Threats Rules on DD-WRT & Restarting Suricata

This is a simple script for updating Emerging Threats rules files and restarting suricata for dd-wrt. Keeping rules updated for the win.

Installing from the terminal (ssh)

Entware is required see more here: https://wiki.dd-wrt.com/wiki/index.php/Installing_Entware

1. Copy et-update.sh in your /opt/bin/ folder and give execute permissions to it chmod +x /opt/bin/et-update.sh
2. Install cron on dd-wrt opkg install cron if you don't have it already.
3. Go to your DD-WRT's Web Interface at Administration -> Management tab, in the Cron field where is says Additional Cron Jobs and paste this line 0 0 * * * root /bin/sh -c /opt/bin/et-update.sh > /dev/null 2>&1
4. In your terminal run the command: stopservice crond && startservice crond and you're done.

It is important though to change inside the script (or leave as is if you're on the same version) the suricata-4.1.8 part from the URL we're fetching the rules from, to match your version of suricata. To find what's yours, simply do a suricata -V -- mine says "This is Suricata version 4.1.8 RELEASE" so I changed it to 4.1.8

By default this cronjob will run every day at 00:00

I personally run suricata on the br0 interface, but it's up to you to change that. Use ifconfig to find the interface that suits you.

Hope someone finds it useful, enjoy :)

Shoutouts

@OISF

https://rules.emergingthreats.net/

DEMO:

This is how it looks like if you run et-update.sh manually on the command line