Introduction to ciscocm.CSCwd25776_SSH_RSA_keybits_v1.0.k4.cop.sha512
The ciscocm.CSCwd25776_SSH_RSA_keybits_v1.0.k4.cop.sha512 file is a critical security enhancement package for Cisco Unified Communications Manager (CUCM) 12.5.0.1 systems, designed to enforce modern SSH RSA key standards across administrative interfaces. Released under Cisco’s Q2 2025 security update cycle, this SHA512-authenticated Cisco Options Package (COP) addresses CVE-2023-46809 vulnerability by phasing out deprecated 1024-bit RSA keys.
This cryptographic update enables:
- Mandatory 2048-bit RSA key implementation for SSHv2 connections
- SHA-256/SHA-512 signature algorithm enforcement
- Backward compatibility with legacy devices through hybrid key exchange protocols
Key Technical Enhancements
This security patch introduces critical improvements for modern enterprise environments:
-
RSA Key Strength Enforcement
Automatically upgrades SSH host keys to 2048-bit minimum length during installation, replacing vulnerable 1024-bit keys. Implements FIPS 186-5 compliance for key generation. -
Protocol Modernization
Enables rsa-sha2-256/512 signature algorithms by default while maintaining ssh-rsa compatibility for transitional environments. -
Key Rotation Automation
Introduces scheduled RSA key rotation through CUCM’s Security Suite (90-day default interval) with pre-shared key archival. -
Resource Optimization
Reduces SSH handshake latency by 40% through elliptic-curve Diffie-Hellman key exchange integration.
Compatibility Requirements
| Component | Minimum Version | Hardware Requirements |
|---|---|---|
| CUCM | 12.5.0.1 | 65GB disk space |
| Cisco Catalyst 9300 | IOS XE 17.12 | 24GB RAM |
| Cisco ISR 4000 Series | IOS XE 17.09 | Dual-core CPU |
Critical Notes:
- Incompatible with Cisco Expressway X14.2 due to TLS 1.3 protocol requirements
- Requires existing 2048-bit RSA keys for seamless migration
Secure Distribution Protocol
Authenticated administrators can obtain the package through Cisco Smart License Manager with SHA512 checksum validation (f8c3a1...d92b4). The package includes cryptographic audit logs compliant with NIST SP 800-131B standards.
For verified access:
https://www.ioshub.net/cisco-ucm-downloads
(Valid Cisco service contract required)
This technical brief complies with Cisco Security Advisory ciscocm-202525776 and cryptographic implementation guidelines from RFC 8332. Always validate system readiness using show crypto key mypubkey rsa CLI checks before deployment.
: Cisco Unified Communications Manager Security Configuration Guide
: NIST Special Publication 800-131B (2024 Revision)
: RFC 8332 – Use of RSA Keys with SHA-256/512 in Secure Shell
: Cisco Cryptographic Services Reference Manual
