ere are the details of the (patched) IPv4 evasion I found in Suricata IDS/IPS: # Software Suricata IDS/IPS website : https://suricata-ids.org/ editor : Open Information Security Foundation (OISF) https://oisf.net/ # Impacted version 3.2.x before 3.2.13.13 3.1.3 and before All execution mode are impacted : nfqueue, af-packet, ... # Vulnerability description Suricata did not used the IP protocol field value to identify fragments from a same packet, whereas the RFC 791 states that 2 fragments should be defragmented together only if the protocol field have the same value. This flaw makes it possible to craft a packet that will only be defragmented by Suricata (and not the destination host), leading to a packet injection in the IDS detection engine. # Impact on security An attacker can fully evade any TCP signature, without any logs / alerts. # Resources and links : New patched Suricata versions : https://suricata-ids.org/2017/02/15/suricata-3-2-1-available/ https://suricata-ids.org/2017/02/15/suricata-3-2-1-available/ Bug tracker and patch commit : https://redmine.openinfosecfoundation.org/issues/2019 https://github.com/inliniac/suricata/commit/4a04f814b15762eb446a5ead4d69d021512df6f8 # Thanks and note I'd like to give a special thanks to the suricata development team and especially Victor Julien : I contacted him concerning the issue, got an answer the same day, and it was corrected on github 2 working days after. Really impressive guys. If anyone needs more information about this, feel free to contact me at jeremy [dot] beaume (a) protonmail [dot] com Cheers ! Jeremy BEAUME