Phones from Cisco do not have their own Web interface but are configured via a provisioning server, the Cisco Unified Communications Manager (CUCM). Those phones can be changed from SCCP to SIP. Because zillions of those phones are sold via eBay, you find a tremendous amount of documentation to get those phones working…
Phones from Sipura do have a Web interface for configuration. Therefore, you need no central configuration server; no need to deal with DHCP, TFTP, and such XML files. Cisco bought Sipura and their Sipura Phone Adapters (SPA). Cisco sold them under (Linksys) SPAxxxG till the year 2016. Then, this platform was named ‘Third-Party Call Control’ until the name of today was introduced: ‘Multiplatform Firmware’ (MPP). Still, their stock-keeping unit (SKU) contains ‘3PCC’. Phones without 3PPC in SKU cannot be changed to this Sipura firmware.
Even before SDES-sRTP was created in 2004, Sipura offered sRTP.
11.2.3 (Administration, Provisioning)
Downloads Home → Collaboration Endpoints → IP Phones → IP Phones with Multiplatform Firmware
retested in Dec. 2019 with 11.3.1
retested in May 2020 with 11.3.1 MSR1-3
| Password: | Web → Voice → System → Admin Password |
| HTTPS: | Web → Voice → System → Enable Protocol: Https Web → Voice → System → Web Server Port: 443 |
| Update: | Web → Voice → Provisioning → (Firmware Upgrade) Upgrade Rule: http:// … .loads |
| Trust Anchors: | Web → Voice → Provisioning → (CA Settings) Custom CA Rule: http:// … .pem built-in trust anchors cannot be viewed |
| SIP-URI Host: | Web → Voice → Att Console → Server Type: Asterisk Web → Voice → Ext 1 → Proxy Web → Voice → Ext 1 → Use DNS SRV Web → Voice → Ext 1 → DNS SRV Auto Prefix |
| SIP-URI User: | Web → Voice → Ext 1 → User ID |
| SIP-over-TLS: | Web → Voice → Ext 1 → SIP Transport: AUTO Web → Voice → Ext 1 → TLS Name Validate |
| SDES-sRTP: | Phone → Cogwheel → User preferences → Call preferences → Secure Call: On (use the central navigation key to change value) → (button) Set which is RTP/AVP with crypto For older models, you have to change Web → Voice → SIP → SRTP Method from the default value ‘x-sipura’ to ‘s-descriptor’. |
| SHA-2 Digest: | ignores algorithm and picks last |
| IP Port Source: | not random on default Mitigation: Web → Voice → SIP → SIP TCP Port Min: 49152-65535 |
| Bugs: | padlock icon even without SIP-over-TLS, and ECDHE curves with less than 224 bit |
| Responsible Disclosure: | via PSIRT team |
| Firmware Update: | missing Automation missing Newsletter |
All of those phones come in several software variants. For this guide to apply, you need an SKU containing 3PCC, like CP-7821-3PCC-K9=.
48 V ?.? A, Coaxial: 5.5 mm × 2.5 mm