Vulnerability CVE-2019-18792


Published: 2020-01-06

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.

Type:

CWE-94

(Improper Control of Generation of Code ('Code Injection'))

CVSS2 => (AV:N/AC:L/Au:N/C:N/I:P/A:P)

CVSS Base Score
Impact Subscore
Exploitability Subscore
6.4/10
4.9/10
10/10
Exploit range
Attack complexity
Authentication
Remote
Low
No required
Confidentiality impact
Integrity impact
Availability impact
None
Partial
Partial
Affected software
Suricata-ids -> Suricata 

 References:
https://github.com/OISF/suricata/commit/1c63d3905852f746ccde7e2585600b2199cefb4b
https://github.com/OISF/suricata/commit/fa692df37a796c3330c81988d15ef1a219afc006
https://redmine.openinfosecfoundation.org/issues/3324
https://redmine.openinfosecfoundation.org/issues/3394

Copyright 2020, cxsecurity.com

 

Back to Top