Practical Interception of DECT Encrypted Voice Communication in Unified Communications Environments

Digital Enhanced Cordless Telephony, DECT, is a worldwide standard for cordless telephony that is frequently integrated into Unified Communications systems both in enterprise and residential environments. DECT supports encryption to protect the confidentiality of the communications whilst allowing the interoperability between products from different models and manufacturers. In this paper we explore, from both a theoretical and a practical standpoint, the security of the DECT cryptographic pairing process which plays a vital role in the security chain of Unified Communications systems involving DECT technology. We demonstrate a practical security attack against the DECT pairing process that is able to retrieve the cryptographic keys and decrypt in real-time any subsequent encrypted voice communication. We also present suggestions for a more secure alternative pairing process that is not vulnerable to this type of passive attack.