CVE-2019-18792
Critical
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.
SeverityCritical
CVSS9.1
Exploit probability85. percentile2.5%
Product
Oisf Suricata
PublishedJan 6, 2020
First seenJan 6, 2020
How to fix
Update
- oisf suricata4.1.6 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| oisf suricata | 4.1.5 ≤ v < 4.1.6, 5.0.0 | 4.1.6 |
| debian debian_linux | 8.0 | — |
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