CVE-2019-18792

Published: 06 January 2020

An issue was discovered in Suricata 5.0.0. It is possible to bypass/evade any tcp based signature by overlapping a TCP segment with a fake FIN packet. The fake FIN packet is injected just before the PUSH ACK packet we want to bypass. The PUSH ACK packet (containing the data) will be ignored by Suricata because it overlaps the FIN packet (the sequence and ack number are identical in the two packets). The client will ignore the fake FIN packet because the ACK flag is not set. Both linux and windows clients are ignoring the injected packet.

Priority

Medium

CVSS 3 base score: 9.1

Status

Package Release Status
suricata
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 21.04 (Hirsute Hippo) Does not exist

Ubuntu 20.10 (Groovy Gorilla) Does not exist

Ubuntu 20.04 LTS (Focal Fossa) Does not exist

Ubuntu 18.04 LTS (Bionic Beaver) Needs triage

Ubuntu 16.04 ESM (Xenial Xerus) Ignored
(end of standard support, was needs-triage)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist