suricata-ids

Suricata before 4.0.4 is prone to an HTTP detection bypass vulnerability in detect.c and stream-tcp.c. If a malicious server breaks a normal TCP flow and sends data before the 3-way handshake is complete, then the data sent by the malicious server will be accepted by web clients such as a web browser or Linux CLI utilities, but ignored by Suricata IDS signatures. This mostly affects IDS signatures for the HTTP protocol and TCP stream content; signatures for TCP packets will inspect such network traffic as usual.

The ProcessMimeEntity function in util-decode-mime.c in Suricata 4.x before 4.0.6 allows remote attackers to cause a denial of service (segfault and daemon crash) via crafted input to the SMTP parser, as exploited in the wild in November 2018.

Suricata version 4.0.4 incorrectly handles the parsing of an EtherNet/IP PDU. A malformed PDU can cause the parsing code to read beyond the allocated data because DecodeENIPPDU in app-layer-enip-commmon.c has an integer overflow during a length check.

Suricata version 4.0.4 incorrectly handles the parsing of the SSH banner. A malformed SSH banner can cause the parsing code to read beyond the allocated data because SSHParseBanner in app-layer-ssh.c lacks a length check.

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.