A control plane for WireGuard

WireGuard is a VPN protocol that has gained significant interest recently. Its main advantages are: (i) simple configuration (via pre-shared SSH-like public keys), (ii) mobility support, (iii) reduced codebase to ease auditing, and (iv) Linux kernel implementation that yields high performance. However, WireGuard (intentionally) lacks a control plane. This means that each peer in a WireGuard network has to be manually configured with the other peers’ public key and IP addresses, or by other means. In this paper we present an architecture based on a centralized server to automatically distribute this information. In a nutshell, first we manually establish a WireGuard tunnel to the centralized server, and ask all the peers to store their public keys and IP addresses in it. Then, WireGuard peers use this secure channel to retrieve on-demand the information for the peers they want to communicate to. Our design strives to: (i) offer a key distribution scheme simpler than PKI-based ones, (ii) limit the number of public keys sent to the peers, and (iii) reduce tunnel establishment latency by means of an UDP-based protocol. We argue that such automation can help the deployment in enterprise or ISP scenarios. We also describe in detail our implementation and analyze several performance metrics. Finally, we discuss possible improvements regarding several shortcomings we found during implementation.This work was partially supported by the Spanish MINECO under contract TEC2017-90034-C2-1-R (ALLIANCE) and the Catalan Institution for Research and Advanced Studies (ICREA).Peer ReviewedPostprint (author's final draft

Creating a VPN Access Point on Raspberry Pi

Tato bakalářská práce se zabývá vytvořením přístupového bodu virtuální privátní sítě (VPN) na jednodeskovém počítači Raspberry Pi. Teoretická část práce popisuje princip VPN, nejrozšířenější tunelovací protokoly a obecně počítač Raspberry Pi s jeho různými generacemi a modely. Zvolené protokoly jsou implementované na Raspberry Pi a je u nich naměřeno hardwarové zatížení, jejich odezva a propustnost. U protokolů je otestována jejich stabilita a zhodnocena spolehlivost.This bachelor thesis deals with creating a virtual private network (VPN) access point on a single-board Raspberry Pi computer. The theoretical part describes the principle of VPN, the most common tunneling protocols and the Raspberry Pi computer in general with its various generations and models. Selected protocols are implemented on the Raspberry Pi and their hardware load, response and throughput are measured. The stability of the protocols is tested and reliability evaluated.

The Security of ChaCha20-Poly1305 in the Multi-user Setting

The ChaCha20-Poly1305 AEAD scheme is being increasingly widely deployed in practice. Practitioners need proven security bounds in order to set data limits and rekeying intervals for the scheme. But the formal security analysis of ChaCha20-Poly1305 currently lags behind that of AES-GCM. The only extant analysis (Procter, 2014) contains a flaw and is only for the single-user setting. We rectify this situation. We prove a multi-user security bound on the AEAD security of ChaCha20-Poly1305 and establish the tightness of each term in our bound through matching attacks. We show how our bound differs both qualitatively and quantitatively from the known bounds for AES-GCM, highlighting how subtle design choices lead to distinctive security properties. We translate our bound to the nonce-randomized setting employed in TLS 1.3 and elsewhere, and we additionally improve the corresponding security bounds for GCM. Finally, we provide a simple yet stronger variant of ChaCha20-Poly1305 that addresses the deficiencies highlighted by our analysis

Implementing ChaCha based crypto primitives on programmable SmartNICs

Control and management plane applications such as serverless function orchestration and 4G/5G control plane functions are offloaded to smartNICs to reduce communication and processing latency. Such applications involve multiple inter-host interactions that were traditionally secured using SSL/TLS gRPC-based communication channels. Offloading the applications to smartNIC implies that we must also offload the security algorithms. Otherwise, we need to send the application messages to the host VM/container for crypto operations, negating offload benefits. We propose crypto externs for Netronome Agilio smartNICs that implement authentication and confidentiality (encryption/decryption) using the ChaCha stream cipher algorithm. AES and ChaCha are two popular cipher suites, but we chose ChaCha since none of the smartNICs have ChaCha-based crypto accelerators. However, smartNICs have restricted instruction set, and limited memory, making it difficult to implement security algorithms. This paper identifies and addresses several challenges to implement ChaCha crypto primitives successfully. Our evaluations show that our crypto extern implementation satisfies the scalability requirement of popular applications such as serverless management functions and host in-band network telemetry. © 2022 ACM

On the Edge of Secure Connectivity via Software-Defined Networking

Securing communication in computer networks has been an essential feature ever since the Internet, as we know it today, was started. One of the best known and most common methods for secure communication is to use a Virtual Private Network (VPN) solution, mainly operating with an IP security (IPsec) protocol suite originally published in 1995 (RFC1825). It is clear that the Internet, and networks in general, have changed dramatically since then. In particular, the onset of the Cloud and the Internet-of-Things (IoT) have placed new demands on secure networking. Even though the IPsec suite has been updated over the years, it is starting to reach the limits of its capabilities in its present form. Recent advances in networking have thrown up Software-Defined Networking (SDN), which decouples the control and data planes, and thus centralizes the network control. SDN provides arbitrary network topologies and elastic packet forwarding that have enabled useful innovations at the network level. This thesis studies SDN-powered VPN networking and explains the benefits of this combination. Even though the main context is the Cloud, the approaches described here are also valid for non-Cloud operation and are thus suitable for a variety of other use cases for both SMEs and large corporations. In addition to IPsec, open source TLS-based VPN (e.g. OpenVPN) solutions are often used to establish secure tunnels. Research shows that a full-mesh VPN network between multiple sites can be provided using OpenVPN and it can be utilized by SDN to create a seamless, resilient layer-2 overlay for multiple purposes, including the Cloud. However, such a VPN tunnel suffers from resiliency problems and cannot meet the increasing availability requirements. The network setup proposed here is similar to Software-Defined WAN (SD-WAN) solutions and is extremely useful for applications with strict requirements for resiliency and security, even if best-effort ISP is used. IPsec is still preferred over OpenVPN for some use cases, especially by smaller enterprises. Therefore, this research also examines the possibilities for high availability, load balancing, and faster operational speeds for IPsec. We present a novel approach involving the separation of the Internet Key Exchange (IKE) and the Encapsulation Security Payload (ESP) in SDN fashion to operate from separate devices. This allows central management for the IKE while several separate ESP devices can concentrate on the heavy processing. Initially, our research relied on software solutions for ESP processing. Despite the ingenuity of the architectural concept, and although it provided high availability and good load balancing, there was no anti-replay protection. Since anti-replay protection is vital for secure communication, another approach was required. It thus became clear that the ideal solution for such large IPsec tunneling would be to have a pool of fast ESP devices, but to confine the IKE operation to a single centralized device. This would obviate the need for load balancing but still allow high availability via the device pool. The focus of this research thus turned to the study of pure hardware solutions on an FPGA, and their feasibility and production readiness for application in the Cloud context. Our research shows that FPGA works fluently in an SDN network as a standalone IPsec accelerator for ESP packets. The proposed architecture has 10 Gbps throughput, yet the latency is less than 10 µs, meaning that this architecture is especially efficient for data center use and offers increased performance and latency requirements. The high demands of the network packet processing can be met using several different approaches, so this approach is not just limited to the topics presented in this thesis. Global network traffic is growing all the time, so the development of more efficient methods and devices is inevitable. The increasing number of IoT devices will result in a lot of network traffic utilising the Cloud infrastructures in the near future. Based on the latest research, once SDN and hardware acceleration have become fully integrated into the Cloud, the future for secure networking looks promising. SDN technology will open up a wide range of new possibilities for data forwarding, while hardware acceleration will satisfy the increased performance requirements. Although it still remains to be seen whether SDN can answer all the requirements for performance, high availability and resiliency, this thesis shows that it is a very competent technology, even though we have explored only a minor fraction of its capabilities

Investigations into Decrypting Live Secure Traffic in Virtual Environments

Malicious agents increasingly use encrypted tunnels to communicate with external servers. Communications may contain ransomware keys, stolen banking details, or other confidential information. Rapid discovery of communicated contents through decrypting tunnelled traffic can support effective means of dealing with these malicious activities.Decrypting communications requires knowledge of cryptographic algorithms and artefacts, such as encryption keys and initialisation vectors. Such artefacts may exist in volatile memory when software applications encrypt. Virtualisation technologies can enable the acquisition of virtual machine memory to support the discovery of these cryptographic artefacts.A framework is constructed to investigate the decryption of potentially malicious communications using novel approaches to identify candidate initialisation vectors, and use these to discover candidate keys. The framework focuses on communications that use the Secure Shell and Transport Layer Security protocols in virtualised environments for different operating systems, protocols, encryption algorithms, and software implementations. The framework minimises virtual machine impact, and functions at an elevated level to make detection by virtual machine software difficult.The framework analyses Windows and Linux memory and validates decrypts for both protocols when the Advanced Encryption Standard symmetric block or ChaCha20 symmetric stream algorithms are used for encryption. It also investigates communications originating from malware clients, such as bot and ransomware, that use Windows cryptographic libraries.The framework correctly decrypted tunnelled traffic with near certainty in almost all experiments. The analysis durations ranged from sub-second to less than a minute, demonstrating that decryption of malicious activity before network session completion is possible. This can enable in-line detection of unknown malicious agents, timely discovery of ransomware keys, and knowledge of exfiltrated confidential information