Network slicing is considered a key enabler to 5th Generation (5G) communication networks. Mobile network operators may deploy network slices-complete logical networks customized for specific services expecting a certain Quality of Service (QoS). New business models like Network Slice-as-a-Service offerings to customers from vertical industries require negotiated Service Level Agreement (SLA) contracts, and network providers need automated enforcement mechanisms to assure QoS during instantiation and operation of slices. In this paper, we focus on ultra-reliable low-latency communication (URLLC). We propose a software architecture for security functions based on offthe-shelf hardware and open-source software and demonstrate, through a series of measurements, that the strict requirements of URLLC services can be achieved. As a real-world example, we perform our experiments using the intrusion prevention system (IPS) Snort to demonstrate the impact of security functions on latency. Our findings lead to the creation of a model predicting the system load that still meets the URLLC latency requirement. We fully disclose the artifacts presented in this paper including pcap traces, measurement tools, and plotting scripts at https://gallenmu.github.io/low-latency.

Shaken by severe compromises, the Web's Public Key Infrastructure has seen the addition of several security mechanisms over recent years. One such mechanism is the Certification Authority Authorization (CAA) DNS record, that gives domain name holders control over which Certification Authorities (CAs) may issue certificates for their domain. First defined in RFC 6844, adoption by the CA/B forum mandates that CAs validate CAA records as of September 8, 2017. The success of CAA hinges on the behavior of three actors: CAs, domain name holders, and DNS operators. We empirically study their behavior, and observe that CAs exhibit patchy adherence in issuance experiments, domain name holders configure CAA records in encouraging but error-prone ways, and only six of the 31 largest DNS operators enable customers to add CAA records. Furthermore, using historic CAA data, we uncover anomalies for already-issued certificates. We disseminated our results in the community. This has already led to specific improvements at several CAs and revocation of mis-issued certificates. Furthermore, in this work, we suggest ways to improve the security impact of CAA. To foster further improvements and to practice reproducible research, we share raw data and analysis tools.

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Linux Containers, such as those managed by Docker, are an increasingly popular way to package and deploy complex applications. However, the fundamental security primitive of network access control for a distributed microservice deployment is often ignored or left to the network operations team. High-level application-specific security requirements are not appropriately enforced by low-level network access control lists. Apart from coarse-grained separation of virtual networks, Docker neither supports the application developer to specify nor the network operators to enforce fine-grained network access control between containers.In a fictional story, we follow DevOp engineer Alice through the lifecycle of a web application. From the initial design and software engineering through network operations and automation, we show the task expected of Alice and propose tool-support to help. As a full-stack DevOp, Alice is involved in high-level design decisions as well as low-level network troubleshooting. Focusing on network access control, we demonstrate shortcomings in today's policy management and sketch a tool-supported solution. We survey related academic work and show that many existing tools fail to bridge between the different levels of abstractions a full-stack engineer is operating on.Our toolset is formally verified using Isabell/HOL and is available as Open Source.