Vulnerability Description
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.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Oisf | Suricata | >= 4.1.5, < 4.1.6 |
| Debian | Debian Linux | 8.0 |
Related Weaknesses (CWE)
References
- https://github.com/OISF/suricata/commit/1c63d3905852f746ccde7e2585600b2199cefb4bPatchThird Party Advisory
- https://github.com/OISF/suricata/commit/fa692df37a796c3330c81988d15ef1a219afc006PatchThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2020/01/msg00032.htmlThird Party Advisory
- https://redmine.openinfosecfoundation.org/issues/3324ExploitThird Party Advisory
- https://redmine.openinfosecfoundation.org/issues/3394ExploitThird Party Advisory
- https://github.com/OISF/suricata/commit/1c63d3905852f746ccde7e2585600b2199cefb4bPatchThird Party Advisory
- https://github.com/OISF/suricata/commit/fa692df37a796c3330c81988d15ef1a219afc006PatchThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2020/01/msg00032.htmlThird Party Advisory
- https://redmine.openinfosecfoundation.org/issues/3324ExploitThird Party Advisory
- https://redmine.openinfosecfoundation.org/issues/3394ExploitThird Party Advisory
FAQ
What is CVE-2019-18792?
CVE-2019-18792 is a vulnerability with a CVSS score of 9.1 (CRITICAL). 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 P...
How severe is CVE-2019-18792?
CVE-2019-18792 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2019-18792?
Check the references section above for vendor advisories and patch information. Affected products include: Oisf Suricata, Debian Debian Linux.