Conference:  Defcon 31

Authors: Dan "AltF4" Petro Senior Security Engineer, Bishop Fox, David Vargas Senior Security Consultant, Bishop Fox

2023-08-01

Breaking into secure facilities used to be possible by inserting a listening device (such as an ESPKey) behind an RFID card reader and sniffing the unencrypted Wiegand badge numbers over the wire as they go to the backend controller. The physical security industry has taken notice and there's a new sheriff in town: The encrypted protocol OSDP which is starting to be rolled into production. Surely encryption will solve our problems and prevent MitM attacks right? ... right? In this presentation, we'll demonstrate over a dozen vulnerabilities, concerning problems, and general "WTF"s in the OSDP protocol that let it be subverted, coerced, and totally bypassed. This ranges from deeply in-the-weeds clever cryptographic attacks, to boneheaded mistakes that undermine the whole thing. We will also demonstrate a practical pentesting tool that can be inserted behind an RFID badge reader to exploit these vulnerabilities. Get your orange vest and carry a ladder, because we're going onsite!