Stephan Huber - I'm on Your Phone Listening: Attacking VoIP Configuration Interfaces

VoIP Phone Security Vulnerabilities

Stephan Huber (Security Researcher, Telekom Security) presents research on enterprise VoIP phone security, discovering critical vulnerabilities in the web management interfaces of major VoIP phone manufacturers.

VoIP Phone Attack Surface

Enterprise VoIP phones run embedded Linux with a web management interface for configuration, firmware updates, and diagnostics. These phones sit on corporate networks with access to audio capture capabilities and internal network segments.

Authentication Bypass CVEs

Huber discovers authentication bypass vulnerabilities in the web management interfaces of Grandstream, Yealink, and Snom VoIP phones — allowing unauthenticated access to configuration pages, SIP credential exports, and diagnostic functions.

Remote Eavesdropping

After authentication bypass, the attacker can activate the phone's speakerphone microphone remotely, capture and exfiltrate all audio in the phone's vicinity, and intercept VoIP call audio — turning every corporate conference room phone into a remote listening device.