Linux Firewalls

Appendix B. A COMPLETE FWSNORT SCRIPT

In this appendix you will find a complete example of an fwsnort.sh script; it was generated by fwsnort for seven different Snort rules from the web-attacks.rules file. These rules are identified by rule IDs 1332, 1336, 1338, 1339, 1341, 1342, and 1360 and are designed to detect attempts by web clients to execute certain commands via a webserver (usually though a CGI program that accepts user input and that is executed by the webserver). These commands are common on Linux systems and include the gcc compiler, nc (Netcat), chown, the C shell chsh, and id (which is used to query UID and GID values assigned to the current user). Any serious attempt on the part of the web client to force the webserver to execute ...