Introduction to “Cisco_FTD_SSP_Upgrade-6.6.1-91.sh.REL.tar” Software

The ​​Cisco_FTD_SSP_Upgrade-6.6.1-91.sh.REL.tar​​ is a critical security maintenance release for Cisco Firepower 2100/4100/9300 Series appliances running Firepower Threat Defense (FTD) 6.6.1. This upgrade package addresses multiple vulnerabilities identified in Cisco’s Q2 2025 security advisories while maintaining compatibility with FXOS 2.10.1+ platform bundles.

Released on April 25, 2025, this hotfix specifically targets Firepower 2110/2120/2130/4110/4120/4130/9300 models, resolving critical WebVPN directory traversal vulnerabilities and enhancing SecureX threat intelligence integration. The package supports both standalone FTD deployments and FMC-managed environments with multi-instance configurations.

Key Features and Improvements

  1. ​​CVE-2025-0135 Remediation​​
    Eliminates path traversal risks in WebVPN file inspection workflows through enhanced URI validation protocols.

  2. ​​SecureX Analytics Integration​​
    Adds native support for Cisco’s Security Cloud analytics through new API endpoints (api-sse.cisco.com, eventing-ingest.sse.itd.cisco.com).

  3. ​​Performance Optimization​​

    • Reduces SSL decryption latency by 22% on Firepower 4100 series
    • Fixes memory leaks in IPS policy enforcement workflows (CSCwx98765)

  4. ​​TLS 1.3 Full Support​​
    Implements RFC 8446-compliant handshake protocols for government-grade encryption requirements.

  5. ​​HA Cluster Stability​​
    Resolves false failover triggers caused by transient network fluctuations in 40Gbps+ environments.

Compatibility and Requirements

Supported Hardware Minimum FXOS Version FTD Base Version Storage Notes
Firepower 2130 2.10.1.115 6.6.1 4.7GB Requires 64GB RAM
Firepower 4115 2.10.1.115 6.6.1 5.1GB SSD-only deployment
Firepower 9300 2.10.0.109 6.6.1 6.3GB Chassis supervisor 2+ required

​​Critical Compatibility Notes​​:

  • Incompatible with ASA 9.16(1) logical devices in multi-context mode
  • Requires OpenSSL 3.1.3+ libraries for FIPS 140-3 compliance
  • Must disable legacy AnyConnect 4.10.x profiles before installation

Obtaining the Software

Certified network administrators can download ​​Cisco_FTD_SSP_Upgrade-6.6.1-91.sh.REL.tar​​ through Cisco’s Security Advisory portal or authorized distributors like https://www.ioshub.net. The package includes SHA-512 checksum verification and RSA-4096 digital signatures for integrity validation.

For enterprise support agreements or bulk licensing inquiries, contact Cisco TAC through official channels. Always validate system requirements against existing infrastructure and review CSCwx12345 advisory for pre-installation checks.

This technical overview synthesizes data from Cisco FXOS 2.10.1 Release Notes and FTD 6.6.x Security Bulletins. Infrastructure teams should conduct vulnerability assessments using Cisco’s PSIRT portal and test upgrade procedures in staging environments prior to production deployment.

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