9.1.2. IP Reputation Rules

IP Reputation can be used in rules through a new rule directive “iprep”.

9.1.2.1. iprep

The iprep directive matches on the IP reputation information for a host.

iprep:<side to check>,<category>,<operator>,<reputation score>

side to check: <any|src|dst|both>

category: the category short name

operator: <, >, =

reputation score: 1-127

Example:

alert ip $HOME_NET any -> any any (msg:"IPREP internal host talking to CnC server"; flow:to_server; iprep:dst,CnC,>,30; sid:1; rev:1;)

This rule will alert when a system in $HOME_NET acts as a client while communicating with any IP in the CnC category that has a reputation score set to greater than 30.

9.1.2.2. IP-only

The “iprep” keyword is compatible to “IP-only” rules. This means that a rule like:

alert ip any any -> any any (msg:"IPREP High Value CnC"; iprep:src,CnC,>,100; sid:1; rev:1;)

will only be checked once per flow-direction.

For more information about IP Reputation see IP Reputation Config and IP Reputation Format.