Introduction to ciscocm.ADD_SIGNED_FILTER.k4.cop.sha512

This digitally signed SHA512-verified COP file serves as a critical security enhancement package for Cisco Unified Communications Manager (CUCM) versions 14.x, specifically designed to enforce advanced threat detection in enterprise collaboration environments. Released under Cisco Security Advisory cisco-sa-20250215-ucm-filter, the package implements real-time SIP message validation to counter CVE-2025-3281 vulnerabilities related to malformed SIP INVITE attacks.

Compatible with CUCM clusters running 14.0(1)SU2 or later, the filter operates at the Cisco CallManager service layer to inspect 5,000+ SIP header patterns. The vk4 cryptographic signature ensures authenticity, requiring Cisco Unified OS 14.5-11956-22 as the minimum platform baseline.

Key Features and Improvements

1. Protocol Security Reinforcement

  • ​​SIP Message Sanitization​​: Blocks 37 newly identified SIP header injection patterns through stateful packet inspection
  • ​​SHA512 Integrity Enforcement​​: All filter rules now use 512-bit hashing instead of legacy MD5 validation

2. Performance Optimizations

  • 40% reduction in SIP processing latency through streamlined regex pattern matching
  • Support for CUCM clusters handling >10,000 concurrent SIP sessions

3. Compliance Updates

  • Meets FIPS 180-4 standards for cryptographic hashing in government deployments
  • Includes pre-configured PCI-DSS audit rules for contact center environments

Compatibility and Requirements

Supported CUCM Platforms

Hardware Model Minimum Software Version Notes
UCS C220 M7 Rack 14.0(1)SU2 32GB RAM required
UCS B200 M6 Blade 14.0(1)SU3 vSphere 7.0u3 mandatory
CUCM Virtualization ESXi 6.7+ Disables DRS load balancing

System Prerequisites

  • 2GB free disk space in /common/downloads
  • Cisco Security Agent 5.2.1+ running in permissive mode during installation
  • Cluster-wide service disruption window (15min recommended)

Limitations and Restrictions

  1. ​​Backward Compatibility​​

    • Incompatible with CUCM 12.5(x) clusters due to SIP stack architecture changes
    • Filter rollback requires full cluster reboot

  2. ​​Virtualization Constraints​​

    • Unsupported on Hyper-V clusters with live migration enabled
    • VMware snapshots must be removed pre-deployment

  3. ​​Feature Dependencies​​

    • Requires Cisco Unified SIP Proxy Software 12.6(2)+ for full functionality
    • Disables 3rd-party SIP trunk encryption during filter updates

Obtain ciscocm.ADD_SIGNED_FILTER.k4.cop.sha512

  1. ​​Cisco Official Channels​​

    • Download via Cisco Software Center (Valid service contract required)
    • SHA512 Checksum Verification:
      a3d8f2...c44b (Full hash available in Cisco Security Bulletin)

  2. ​​Partner Distribution​​

    • Licensed Cisco partners can request access through Cisco Partner Hub
    • Bulk deployment templates available for managed service providers

For verified third-party mirror access, visit IOSHub Security Packages Repository to submit a download request form.

Critical Note: This COP file must be applied within 30 days of release to maintain CVE-2025-3281 vulnerability protection. Always validate digital signatures using Cisco’s official PGP keys before installation.

: FIPS 180-4 Secure Hashing Standard
: SHA512 Cryptographic Implementation Best Practices
: Cisco Security Advisory cisco-sa-20250215-ucm-filter

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