CVE-2019-18792

Public Exploit

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.

Category

9.1
CVSS
Severity: Critical
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.25%
Third-Party Advisory github.com Third-Party Advisory github.com Third-Party Advisory debian.org Third-Party Advisory openinfosecfoundation.org Third-Party Advisory openinfosecfoundation.org
Affected: n/a n/a
Published at:
Updated at:

References

Link Tags
https://redmine.openinfosecfoundation.org/issues/3324 third party advisory exploit
https://github.com/OISF/suricata/commit/fa692df37a796c3330c81988d15ef1a219afc006 third party advisory patch
https://redmine.openinfosecfoundation.org/issues/3394 third party advisory exploit
https://github.com/OISF/suricata/commit/1c63d3905852f746ccde7e2585600b2199cefb4b third party advisory patch
https://lists.debian.org/debian-lts-announce/2020/01/msg00032.html third party advisory mailing list

Frequently Asked Questions

What is the severity of CVE-2019-18792?
CVE-2019-18792 has been scored as a critical severity vulnerability.
How to fix CVE-2019-18792?
To fix CVE-2019-18792, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2019-18792 being actively exploited in the wild?
It is possible that CVE-2019-18792 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
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