Cisco FTD: CVE-2023-20177: Cisco Firepower Threat Defense Software SSL/TLS URL Category and Snort 3 Detection Engine Bypass and Denial of Service Vulnerability

Cisco FTD: CVE-2023-20177: Cisco Firepower Threat Defense Software SSL/TLS URL Category and Snort 3 Detection Engine Bypass and Denial of Service Vulnerability

Severity

3

CVSS

(AV:N/AC:H/Au:N/C:N/I:N/A:P)

Published

11/01/2023

Created

02/07/2025

Added

01/29/2025

Modified

02/12/2025

Description

A vulnerability in the SSL file policy implementation of Cisco Firepower Threat Defense (FTD) Software that occurs when the SSL/TLS connection is configured with a URL Category and the Snort 3 detection engine could allow an unauthenticated, remote attacker to cause the Snort 3 detection engine to unexpectedly restart. This vulnerability exists because a logic error occurs when a Snort 3 detection engine inspects an SSL/TLS connection that has either a URL Category configured on the SSL file policy or a URL Category configured on an access control policy with TLS server identity discovery enabled. Under specific, time-based constraints, an attacker could exploit this vulnerability by sending a crafted SSL/TLS connection through an affected device. A successful exploit could allow the attacker to trigger an unexpected reload of the Snort 3 detection engine, resulting in either a bypass or denial of service (DoS) condition, depending on device configuration. The Snort 3 detection engine will restart automatically. No manual intervention is required.

Solution(s)

• cisco-ftd-upgrade-latest

References

• https://attackerkb.com/topics/cve-2023-20177
• CVE - 2023-20177
• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sa-ftd-snort3-urldos-OccFQTeX
• cisco-sa-sa-ftd-snort3-urldos-OccFQTeX