Vulnerability in Oisf Suricata

CVE-2021-45098

An issue was discovered in Suricata before 6.0.4. It is possible to bypass/evade any HTTP-based signature by faking an RST TCP packet with random TCP options of the md5header from the client side. After the three-way handshake, it's possible to inject an RST ACK with a random TCP md5header option. Then, the client can send an HTTP GET request with a forbidden URL. The server will ignore the RST ACK and send the response HTTP packet for the client's request. These packets will not trigger a Suricata reject action.

EPSS: 0.018 (76.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

Affected products

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-45098?
CVE-2021-45098 is a high-severity vulnerability in Oisf Suricata. CVSS score: 7.5/10. Published 2021-12-16.
How severe is CVE-2021-45098?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2021-45098 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.