With the rapid development of health equipments, increasingly more patients have installed the implantable medical devices (IMD) in their bodies for diagnostic, monitoring, and therapeutic purposes. IMDs are extremely limited in computation power and battery capacity. Meanwhile, IMDs have to communicate with an external programmer device (i.e., IMD programmer) through the wireless channel, which put them under the risk of unauthorized access and malicious wireless attacks. In this paper, we propose a proxy-based fine-grained access control scheme for IMDs, which can prolong the IMD's lifetime by delegating the access control computations to the proxy device (e.g., smartphone). In our scheme, the proxy communicates with the IMD programmer through an audio cable, which is resistant to a number of wireless attacks. Additionally, we use the ciphertext-policy attribute-based encryption (CP-ABE) to enforce fine-grained access control. The proposed scheme is implemented on real emulator devices and evaluated through experimental tests. The experiments show that the proposed scheme is lightweight and effective.
Implantable Medical Devices (IMDs) have been widely used to treat chronic diseases such as cardiac arrhythmia and diabetes. Many IMDs are enabled with wireless communication capabilities and can communicate with an outside programmer reader wirelessly. With the rapid growth of IMDs, IMD security becomes a critical issue since attacks on IMDs may directly harm the patient. Typical IMDs have very limited resource in terms of energy, computation and storage. In this research, we identify a new kind of attacks on IMDs -Resource Depletion (RD) attacks that could deplete IMD resources (e.g., battery power) quickly. The RD attacks could reduce the lifetime of an IMD from several years to a few weeks. The attacks can be easily launched but can not be defended by traditional cryptographic approaches. In this paper, we propose to utilize the patient's IMD access pattern and we design a novel Support Vector Machine (SVM) based scheme to address the RD attacks. Our SVM-based scheme is very effective in defending the RD attacks. Our experimental results show that the average detection rate of the SVM-based scheme is above 90 . Rapid advances in personal healthcare systems based on implantable and wearable medical devices promise to greatly improve the quality of diagnosis and treatment for a range of medical conditions. However, the increasing programmability and wireless connectivity of medical devices also open up opportunities for malicious attackers. Unfortunately, implantable wearable medical devices come with extreme size and power constraints, and unique usage models, making it infeasible to simply borrow conventional security solutions such as cryptography. We propose a general framework for securing medical devices based on wireless channel monitoring and anomaly detection. Our proposal is based on a medical security monitor (MedMon) that snoops on all the radio-frequency wireless communications to from medical devices and uses multi-layered anomaly detection to identify potentially malicious transactions. Upon detection of a malicious transaction, MedMon takes appropriate response actions, which could range from passive (notifying the user) to active (jamming the packets so that they do not reach the medical device). A key benefit of MedMon is that it is applicable to existing medical devices that are in use by patients, with no hardware or software modifications to them. Consequently, it also leads to zero power overheads on these devices. We demonstrate the feasibility of our proposal by developing a prototype implementation for an insulin delivery system using off-the-shelf components (USRP software-defined radio). We evaluate its effectiveness under several attack scenarios. Our results show that MedMon can detect virtually all naive attacks and a large fraction of more sophisticated attacks, suggesting that it is an effective approach to enhancing the security of medical devices. A fundamental tension exists between safety in the common case and security under adversarial conditions for wireless implantable medical devices. We propose a class of new, fail-open defensive techniques for implantable medical devices that attempt to strike a balance between these two goals. We refer to these defensive techniques as Communication Cloakers. Cloakers are externally worn devices, much like computational Medical Alert bracelets. Cloakers protect the security of an IMD when worn, but allow for open access during emergencies if removed. Recent studies have revealed security vulnerabilities in implantable medical devices (IMDs). Security design for IMDs is complicated by the requirement that IMDs remain operable in an emergency when appropriate security credentials may be unavailable. In this paper, we introduce IMDGuard, a comprehensive security scheme for heart-related IMDs to fulfill this requirement. IMDGuard incorporates two techniques tailored to provide desirable protections for IMDs. One is an ECG based key establishment without prior shared secrets, and the other is an access control mechanism resilient to adversary spoofing attacks. The security and performance of IMDGuard are evaluated on our prototype implementation.