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Voice over 4G, or VoLTE, brings back the phreaking 80’s. Once again, after 3 decades, the signaling path of telephony is accessible to end users. No more R1, R2, C4 or C5 however: we now have SIP. As it turns out, the implementations of SIP and VoLTE in various European providers’ 4G infrastructures, open up a host of possibilities. During our research over the past few years we have identified vulnerabilities in implementations such as text message spoofing, subscriber enumeration, location determination (leakage of cell-ID and LAC), IMEI leakage and a potential SIM-card sharing attack.