Last Modified: May 14, 2019
See more info
Known Affected Versions:
13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1, 13.1.0, 220.127.116.11, 18.104.22.168, 22.214.171.124, 126.96.36.199, 188.8.131.52, 184.108.40.206, 220.127.116.11, 18.104.22.168, 13.1.1, 22.214.171.124
Opened: Nov 27, 2017
AFM might generate a dynamic signature for those bins that have a very low learnt threshold during the learning phase, if the current traffic rate spikes and increases above the anomaly threshold floor db variable value as specified by l4bdos.anomaly.threshold.floor
This might cause AFM to generate signatures with higher false positives. This is specifically due to incorrect application of db variable setting 'l4bdos.anomaly.threshold.floor' that should be interpreted as the 'floor' value of learnt thresholds for any bin. So, if the learnt threshold of a bin is lower than this db variable, the baseline threshold of the bin should be set to the db variable for anomaly detection phase.
AFM dynamic signature feature is enabled.
There is no workaround at this time.
This issue is fixed by making sure that db variable 'l4bdos.anomaly.threshold.floor' is used as the 'floor' value of baseline thresholds for those bins that have a learnt threshold lower than this db variable.