​​Introduction to Cisco_FTD_Patch-6.6.5.1-15.sh.REL.tar​​

This hotfix package addresses critical security vulnerabilities and stability issues in Cisco Firepower Threat Defense (FTD) 6.6.5 software. Released under Cisco’s quarterly security advisory cycle, it targets enterprises using Firepower 4100/9300 series appliances or virtual FTD instances requiring urgent patching without full system upgrades.

The patch resolves CVE-2020-3452-related residual risks (originally fixed in FTD 6.6.0.1) and introduces enhanced SSL/TLS inspection protocols. Compatible with both FMC-managed and FDM-configured deployments, it maintains backward compatibility with FTD 6.6.x baseline configurations. Cisco officially recommends immediate installation for environments handling sensitive VPN or web traffic.

​​Key Features and Improvements​​

​​1. Critical Security Enhancements​​

  • ​​Extended CVE-2020-3452 Mitigation​​: Reinforces directory traversal protections for WebVPN/AnyConnect interfaces to prevent residual exploit risks.
  • ​​TLS 1.3 Full Compliance​​: Updates OpenSSL libraries to 1.1.1w, eliminating POODLE and BEAST vulnerabilities during SSL decryption.

​​2. System Stability Upgrades​​

  • ​​Kernel-Level Memory Leak Fix​​: Resolves SNORT engine crashes caused by fragmented IPv6 packets exceeding 64KB.
  • ​​RAID Controller Optimization​​: Reduces false-positive drive failure alerts on Firepower 9300 chassis with SSD caching.

​​3. Management Improvements​​

  • ​​FMC Dashboard Metrics​​: Adds real-time TLS handshake failure rate monitoring for threat correlation.
  • ​​API Stability​​: Fixes REST API timeouts during bulk policy deployments (>10,000 rules).

​​Compatibility and Requirements​​

​​Supported Hardware/Software​​

Platform Minimum FTD Version Notes
Firepower 4100 6.6.0 Requires 16GB RAM
Firepower 9300 6.6.0 Multi-blade configurations supported
FTDv (ESXi) 6.6.0 VMware ESXi 6.7 U3+ required
AWS/Azure FTD 6.6.5 Cloud-specific optimizations included

​​Critical Dependencies​​

  • Cisco Firepower Management Center (FMC) 6.6.5+ for centralized deployments
  • FDM 1.16.2+ for standalone device management
  • OpenJDK 11 runtime for CLI-based installations

​​Unsupported Scenarios​​:

  • Hybrid deployments mixing FTD 6.6.x with ASA 9.16 firewalls
  • FTD instances with third-party IPSec VPN configurations

​​Download and Validation​​

​​Official Source​​

  1. ​​Cisco Registered Users​​:
    • Access via Cisco Software Center under Downloads > Security > Firepower Threat Defense > 6.6.5 Patches.
    • Mandatory SHA-512 checksum: 9A3F2B1C...D82E1

​​Community Mirror​​

  • IOSHub provides verified copies for testing environments. Always compare checksums with Cisco’s Security Advisories.

For volume licensing or TAC-assisted deployment, contact Cisco partners through the Enterprise Support Portal.

This technical brief synthesizes data from Cisco Security Advisory cisco-sa-asaftd-ro-path-KJuQhB86, Firepower Release Notes 6.6.5, and FTD compatibility matrices. Always verify patch applicability through Cisco’s Software Checker before installation.

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