PinDr0p: using single-ended audio features to determine call provenance

The recent diversification of telephony infrastructure allows users to communicate through landlines, mobile phones and VoIP phones. However, call metadata such as Caller-ID is either not transferred or transferred without verification across these networks, allowing attackers to maliciously alter it. In this paper, we develop PinDr0p, a mechanism to assist users in determining call provenance -- the source and the path taken by a call. Our techniques detect and measure single-ended audio features to identify all of the applied voice codecs, calculate packet loss and noise profiles, while remaining agnostic to characteristics of the speaker's voice (as this may legitimately change when interacting with a large organization). In the absence of verifiable call metadata, these features in combination with machine learning allow us to determine the traversal of a call through as many as three different providers (e.g., cellular, then VoIP, then PSTN and all combinations and subsets t...

• Type: Conference
• Year: 2010
• Where: CCS
• Authors: Vijay A. Balasubramaniyan, Aamir Poonawalla, Mustaque Ahamad, Michael T. Hunter, Patrick Traynor
• Keywords: Applied Voice Codecs, CCS 2010, Security Privacy, Single-ended Audio Features, Telephony Infrastructure