# Configure Thresholding and Suppression # ====================================== # # Thresholding: # # This feature is used to reduce the number of logged alerts for noisy rules. # This can be tuned to significantly reduce false alarms, and it can also be # used to write a newer breed of rules. Thresholding commands limit the number # of times a particular event is logged during a specified time interval. # There are 3 types of thresholding: # # 1) Limit # Alert on the 1st M events during the time interval, then ignore # events # for the rest of the time interval. # 2) Threshold # Alert every M times we see this event during the time interval. # 3) Both # Alert once per time interval after seeing M occurrences of the # event, # then ignore any additional events during the time interval. # # Threshold commands are formatted as: # threshold gen_id gen-id, sig_id sig-id, type limit|threshold|both, track # by_src|by_dst, count n , seconds m # # Limit to logging 1 event per 60 seconds # threshold gen_id 1, sig_id 1851, type limit, track by_src, count 1, seconds # 60 # Global Threshold - Limit to logging 1 event per 60 seconds per IP triggering # each rule (rules are gen_id 1). # threshold gen_id 1, sig_id 0, type limit, track by_src, count 1, seconds 60 # Global Threshold - Limit to logging 1 event per 60 seconds per IP triggering # any alert for any event generator # threshold gen_id 0, sig_id 0, type limit, track by_src, count 1, seconds 60 # # Thresholding does not need to be a stand-alone command, and can instead be # written directly into a rule. Please see README.thresholding for more # information on thresholding. # # Suppression: # # Suppression commands are standalone commands that reference generators and # sids and IP addresses via a CIDR block. This allows a rule to be completely # suppressed, or suppressed when the causitive traffic is going to or comming # from a specific IP or group of IP addresses. # # Suppress this event completely # # suppress gen_id 1, sig_id 1852 # # Suppress this event from this IP # # suppress gen_id 1, sig_id 1852, track by_src, ip 10.1.1.54 # # Suppress this event to this CIDR block # # suppress gen_id 1, sig_id 1852, track by_dst, ip 10.1.1.0/24