Johanna Ullrich

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We define and study cloudoscopy, i.e., exposing sensitive information about the location of (victim) cloud services and/or about the internal organisation of the cloud network, in spite of location-hiding efforts by cloud providers. A typical cloudoscopy attack is composed of a number of steps: first expose the internal IP address of a victim instance, then(More)
The history of computers is full of underestimation: 640 kilobyte, 2-digit years, and 32-bit Internet addresses. IPv6 was invented to overcome the latter as well as to revise other drawbacks and security vulnerabilities of its predecessor IPv4. Initially considered the savior in terms of security because of its mandatory IPsec support, it turned out not to(More)
2D barcodes offer many benefits compared to 1D barcodes, such as high information density and robustness. Before their introduction to the mobile phone ecosystem, they have been widely used in specific applications, such as logistics or ticketing. However, there are multiple competing standards with different benefits and drawbacks. Therefore, reader(More)
Today's capability of fast Internet-wide scanning allows insights into the Internet ecosystem, but the on-going transition to the new Internet Protocol version 6 (IPv6) makes the approach of probing all possible addresses infeasible, even at current speeds of more than a million probes per second. As a consequence, the exploitation of frequent patterns has(More)
Cloud computing is playing an ever larger role in the IT infrastructure. The migration into the cloud means that we must rethink and adapt our security measures. Ultimately, both the cloud provider and the customer have to accept responsibilities to ensure security best practices are followed. Firewalls are one of the most critical security features. Most(More)
Intentionally inserted malfunctions in integrated circuits, referred to as Hardware Trojans, have become an emerging threat. Recently, the scientific community started to propose technical approaches to mitigate the threat of unspecified and potentially malicious functionality. However, these detection and prevention mechanisms are still hardly integrated(More)
Local-area networks comprising the Internet of Things (IoT) consist mainly of devices that have limited processing capabilities and face energy constraints. This has an implication on developing security mechanisms, as they require significant computing resources. In this paper, we design a trust-based routing solution with IoT devices in mind.(More)
QR codes have emerged as a popular medium to make content instantly accessible. With their high information density and robust error correction, they have found their way to the mobile ecosystem. However, QR codes have also proven to be an efficient attack vector, e.g. To perform phishing attacks. Attackers distribute malicious codes under false pretenses(More)