Unlocking secrets of the Proxmark3 RDV4.0 | Kevin Barker & Christian Herrmann | nullcon Goa 2019

### Overview In this talk presented at nullcon Goa 2019, Kevin Barker (handle: 0xffff) and Christian Herrmann (known in the RFID community as Iceman) introduce the Proxmark3 RDV4.0, the latest iteration of the open-source RFID and NFC research platform. Reflecting on over a decade of community-driven hardware and software development within RFID research, the speakers showcase the physical redesign, enhanced capabilities, and new firmware features integrated into the RRG repository. They demonstrate practical attacks and evaluation workflows targeting smart cards, Mifare credentials, and dual-interface payment systems.

### Key Topics - **Evolution of the Proxmark3 Hardware**: Comparison between the bulky legacy versions (such as the original board created by Jonathan Westhues featuring clumsy Hirose connectors and limited expansion) and the new RDV4.0, which shrinks the footprint to credit-card size while enhancing build quality. - **Hardware & Interface Advancements**: Introduction of modular antenna options (dual 125/134 kHz LF and 13.56 MHz HF), FPC expansion for active antennas, Bluetooth/battery options for covert red-team operations, an onboard 2 Mb flash memory chip, and an ISO/IEC 7816 smart card contact module. - **Mifare Cracking & Nested Attacks**: Practical demonstrations of default key testing, Darkside attacks, and advanced hard-nested attacks leveraging optimized bit-slice solvers and parity leak techniques. - **Contact and Dual-Interface Card Analysis**: Using the add-on smart card module to communicate directly via ISO 7816 with raw APDUs, parse EMV credentials (such as Visa cards) across both contact and contactless interfaces, and evaluate cards for cryptographic weaknesses such as the ROCA vulnerability. - **Hotel and Physical Access Case Studies**: References to real-world incidents, including the Tesla Model S key fob cloning and the VingCard (Vision) hotel card vulnerability impacting millions of locks.

### Technical Details - **Hardware Architecture**: The RDV4.0 incorporates 2 Mb of onboard flash memory configured as four 64 KB pages divided into 4 KB sectors. This onboard storage allows dictionary files and cryptographic keys to be stored directly on the device, accelerating dictionary lookups (reducing search time to ~5.6–5.9 seconds) and enabling standalone operations without a tethered computer. - **Tuning and Diagnosis**: Using commands like `hw version`, `hw status`, and `hw tune`, operators can inspect FPGA configurations, verify connected modules (e.g., smart card firmware at version 3.10+), and measure LF/HF antenna peak voltages (e.g., ~45V LF, ~50V HF) to ensure optimal resonant coupling. - **Mifare Classic & Hard-Nested Attacks**: The speakers detail how newer Mifare Classic revisions with hardened PRNGs mitigated classic Darkside attacks. However, exploiting research into parity leakage and utilizing multi-threaded bit-slice solvers implemented by community members (such as piwi and iceman) dramatically lowered nonce requirements from 40,000–50,000 nonces to roughly 1,600 nonces, enabling sector keys to be recovered in minutes. Herrmann demonstrates this using scripts (`autopwn`) that recover keys, dump card memory, and export data directly into binary, EML, JSON, and readable HTML formats. - **ISO 7816 & EMV Operations**: Utilizing the new `sc` and `emv` commands, the RDV4.0 captures Answer to Reset (ATR) data, exchanges raw APDUs, decodes EMV TLV data, and assesses RSA key generation for vulnerabilities like ROCA (Return of Coppersmith's Attack).

### Takeaways - **Hardware Maturity**: The Proxmark3 RDV4.0 delivers a rugged, covert, and highly expandable form factor tailored for professional penetration testers and hardware researchers. - **Firmware Ecosystem**: Users are urged to flash the official RRG repository firmware rather than outdated legacy forks to leverage modern multi-threaded solvers, standalone execution, and bug fixes. - **Defense in Depth for RFID**: Relying on default keys or static UIDs leaves access control systems critically exposed. Even hardened cards require distinct, non-default cryptographic keys across all sectors to prevent nested cryptanalytic recovery.