A vulnerability in the interaction between the TCP Intercept feature and the Snort 3 detection engine on Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass configured policies on an affected system. Devices that are configured with Snort 2 are not affected by this vulnerability. 

 This vulnerability is due to a logic error when handling embryonic (half-open) TCP connections. An attacker could exploit this vulnerability by sending a crafted traffic pattern through an affected device. A successful exploit could allow unintended traffic to enter the network protected by the affected device.

Cisco Systems, Inc. AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Cisco Systems, Inc. CWE-399

Cisco Systems, Inc. https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort-bypass-PTry37fX [No types assigned]