An issue was discovered in Suricata 4.1.x before 4.1.4. If the input of the function SSHParseBanner is composed only of a \n character, then the program runs into a heap-based buffer over-read. This occurs because the erroneous search for \r results in an integer underflow.

An issue was discovered in Suricata 5.0.0. It was possible to bypass/evade any tcp based signature by faking a closed TCP session using an evil server. After the TCP SYN packet, it is possible to inject a RST ACK and a FIN ACK packet with a bad TCP Timestamp option. The client will ignore the RST ACK and the FIN ACK packets because of the bad TCP Timestamp option. Both linux and windows client are ignoring the injected packets.

A buffer over-read issue was discovered in Suricata 4.1.x before 4.1.4. If the input of the decode-mpls.c function DecodeMPLS is composed only of a packet of source address and destination address plus the correct type field and the right number for shim, an attacker can manipulate the control flow, such that the condition to leave the loop is true. After leaving the loop, the network packet has a length of 2 bytes. There is no validation of this length. Later on, the code tries to read at an empty position, leading to a crash.

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.

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 before 4.0.5 stops TCP stream inspection upon a TCP RST from a server. This allows detection bypass because Windows TCP clients proceed with normal processing of TCP data that arrives shortly after an RST (i.e., they act as if the RST had not yet been received).

An issue was discovered in Suricata before 3.1.2. If an ICMPv4 error packet is received as the first packet on a flow in the to_client direction, it confuses the rule grouping lookup logic. The toclient inspection will then continue with the wrong rule group. This can lead to missed detection.

OISF suricata-update version 1.0.0a1 contains an Insecure Deserialization vulnerability in the insecure yaml.load-Function as used in the following files: config.py:136, config.py:142, sources.py:99 and sources.py:131. The "list-sources"-command is affected by this bug. that can result in Remote Code Execution(even as root if suricata-update is called by root). This attack appears to be exploitable via a specially crafted yaml-file at https://www.openinfosecfoundation.org/rules/index.yaml. This vulnerability appears to have been fixed in 1.0.0b1.

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.