CVE-2021-45098 Information

Description

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.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Reference

https://github.com/OISF/suricata/releases https://redmine.openinfosecfoundation.org/issues/4710 https://forum.suricata.io/t/suricata-6-0-4-and-5-0-8-released/1942 https://github.com/OISF/suricata/commit/50e2b973eeec7172991bf8f544ab06fb782b97df

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

HIGH

Base Score

NONE

Base Severity

7.5