High CVSS 7.5

Overview

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.

Risk analysis

This vulnerability is rated 🟠 HIGH.

  • CVSS: 7.5 (HIGH)
  • Detected tags: none (tag impact: LOW)

Recommended actions:

  • Prioritize remediation based on business criticality and exposure.
  • Limit exposure and increase monitoring until fixed.

Recommended tools

Tags