CVEvulnerability

CVE-2019-18792

9.1 CRITICAL Published 2020-01-06 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2020-01-06
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
9.1 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
CVSS 2.0 ([email protected])
6.4 MEDIUM — AV:N/AC:L/Au:N/C:N/I:P/A:P
Weaknesses
CWE-436

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.

Affected configurations

• oisf suricata (>= 4.1.5 < 4.1.6) • oisf suricata 5.0.0 • debian debian linux 8.0

Related

Weakness · CWE (1)

  • CWE-436 Interpretation Conflict weakness

References