TY - CHAP A1 - Meyer, Christopher A1 - Somorovsky, Juraj A1 - Weiss, Eugen A1 - Schwenk, Jörg A1 - Schinzel, Sebastian A1 - Tews, Erik T1 - Revisiting SSL/TLS Implementations: New Bleichenbacher Side Channels and Attacks. T2 - 23rd USENIX Security Symposium (USENIX Security 14) Y1 - 2014 SN - ISBN 978-1-931971- SP - 733 EP - -748 PB - USENIX Association CY - San Diego, CA ER - TY - CHAP A1 - Schmitt, Isabell A1 - Schinzel, Sebastian T1 - WAFFle: Fingerprinting Filter Rules of Web Application Firewalls T2 - 6th USENIX Workshop on Offensive Technologies (WOOT 2012) Y1 - 2012 SP - 34 EP - 40 CY - Seattle. ER - TY - CHAP A1 - Schinzel, Sebastian T1 - An Efficient Mitigation Method for Timing Side Channels on the Web T2 - 2nd International Workshop on Constructive Side-Channel Analysis and Secure Design (COSADE 2011) Y1 - 2011 ER - TY - CHAP A1 - Atkinson, Colin A1 - Gerbig, Ralph A1 - Barth, Florian A1 - Freiling, Felix A1 - Schinzel, Sebastian A1 - Hadasch, Frank A1 - Maedche, Alexander A1 - Müller, Benjamin T1 - Reducing the Incidence of Unintended, Human-Caused Information Flows in Enterprise Systems T2 - Enterprise Distributed Object Computing Conference Workshops (EDOCW), 2012 IEEE 16th International Y1 - 2012 U6 - http://dx.doi.org/10.1109/EDOCW.2012.12 SP - 11 EP - 18 ET - 3M4SE 2012 ER - TY - CHAP A1 - Schinzel, Sebastian A1 - Schmucker, Martin A1 - Ebinger, Peter T1 - Security mechanisms of a legal peer-to-peer file sharing system (http://www.iadis.net/dl/Search_list_open.asp?code=6365) T2 - IADIS International Journal on Computer Science and Information Systems Y1 - 2009 ER - TY - CHAP A1 - Ebinger, Peter A1 - Schinzel, Sebastian A1 - Schmuckler, Martin T1 - Security mechanisms of a legal peer-to-peer file sharing system T2 - IADIS International Conference Applied Computing Y1 - 2008 ER - TY - JOUR A1 - Schinzel, Sebastian T1 - Side Channel Attacks: Error messages and verbose log entries can tip off intruders JF - LINUX Magazine Y1 - 2012 IS - #143 ER - TY - CHAP A1 - Bauer, Johannes A1 - Schinzel, Sebastian A1 - Felix, C. A1 - Freiling, Andreas T1 - Information leakage behind the curtain: Abusing anti-EMI features for covert communication T2 - Hardware Oriented Security and Trust (HOST), 2016 IEEE International Symposium on Y1 - 2016 U6 - http://dx.doi.org/10.1109/HST.2016.7495570 SP - 130 EP - 134 ER - TY - BOOK A1 - Schinzel, Sebastian T1 - Unintentional and Hidden Information Leaks in Networked Software Applications Y1 - 2012 SP - 1 EP - 103 CY - University of Erlangen-Nuernberg ET - Dissertation ER - TY - CHAP A1 - Schumilo, Sergej A1 - Aschermann, Cornelius A1 - Gawlik, Robert A1 - Schinzel, Sebastian A1 - Holz, Thorsten T1 - kAFL: Hardware-Assisted Feedback Fuzzing for OS Kernels T2 - 26th Usenix Security Symposium Y1 - 2017 ER - TY - CHAP A1 - Poddebniak, Damian A1 - Dresen, Christian A1 - Müller, Jens A1 - Ising, Fabian A1 - Schinzel, Sebastian A1 - Friedberg, Simon A1 - Somorovsky, Juraj A1 - Schwenk, Jörg T1 - Efail: Breaking S/MIME and OpenPGP Email Encryption using Exfiltration Channels T2 - USENIX Security 2018 Y1 - 2018 SN - 978-1-931971-46-1 CY - Baltimore, MD, USA ET - 27th ER - TY - CHAP A1 - Müller, Jens A1 - Ising, Fabian A1 - Mldadenov, Vladislav A1 - Mainka, Christian A1 - Schinzel, Sebastian A1 - Schwenk, Jörg T1 - Practical Decryption exFiltration: Breaking PDF Encryption T2 - The 26th ACM Conference on Computer and Communications, Security (CCS 2019), London, United Kingdom N2 - The Portable Document Format, better known as PDF, is one of themost widely used document formats worldwide, and in order to en-sure information confidentiality, this file format supports documentencryption. In this paper, we analyze PDF encryption and showtwo novel techniques for breaking the confidentiality of encrypteddocuments. First, we abuse the PDF feature ofpartially encrypteddocuments to wrap the encrypted part of the document withinattacker-controlled content and therefore, exfiltrate the plaintextonce the document is opened by a legitimate user. Second, we abusea flaw in the PDF encryption specification to arbitrarily manipulateencrypted content. The only requirement is that a single block ofknown plaintext is needed, and we show that this is fulfilled bydesign. Our attacks allow the recovery of the entire plaintext of en-crypted documents by using exfiltration channels which are basedon standard compliant PDF properties.We evaluated our attacks on 27 widely used PDF viewers andfound all of them to be vulnerable. We responsibly disclosed thevulnerabilities and supported the vendors in fixing the issue Y1 - 2019 UR - https://pdf-insecurity.org/download/paper-pdf_encryption-ccs2019.pdf U6 - http://dx.doi.org/10.1145/3319535.3354214 ER - TY - CHAP A1 - Dresen, Christian A1 - Ising, Fabian A1 - Poddebniak, Damian A1 - Kappert, Tobias A1 - Holz, Thorsten A1 - Schinzel, Sebastian ED - Zhou, Jianying T1 - CORSICA: Cross-Origin Web Service Identification T2 - The 15th ACM ASIA Conference on Computer and Communications Security N2 - Vulnerabilities in private networks are difficult to detect for attackers outside of the network. While there are known methods for port scanning internal hosts that work by luring unwitting internal users to an external web page that hosts malicious JavaScript code, no such method for detailed and precise service identification is known. The reason is that the Same Origin Policy (SOP) prevents access to HTTP responses of other origins by default. We perform a structured analysis of loopholes in the SOP that can be used to identify web applications across network boundaries. For this, we analyze HTML5, CSS, and JavaScript features of standard-compliant web browsers that may leak sensitive information about cross-origin content. The results reveal several novel techniques, including leaking JavaScript function names or styles of cross-origin requests that are available in all common browsers. We implement and test these techniques in a tool called CORSICA. It can successfully identify 31 of 42 (74%) of web services running on different IoT devices as well as the version numbers of the four most widely used content management systems WordPress, Drupal, Joomla, and TYPO3. CORSICA can also determine the patch level on average down to three versions (WordPress), six versions (Drupal), two versions (Joomla), and four versions (TYPO3) with only ten requests on average. Furthermore, CORSICA is able to identify 48 WordPress plugins containing 65 vulnerabilities. Finally, we analyze mitigation strategies and show that the proposed but not yet implemented strategies Cross-Origin Resource Policy (CORP)} and Sec-Metadata would prevent our identification techniques. Y1 - 2020 UR - https://asiaccs2020.cs.nthu.edu.tw/program/ ER - TY - CHAP A1 - Saatjohann, Christoph A1 - Ising, Fabian A1 - Krings, Luise A1 - Schinzel, Sebastian T1 - STALK: security analysis of smartwatches for kids T2 - ARES 2020: The 15th International Conference on Availability, Reliability and Security / Editors: Melanie Volkamer, Christian Wressnegger N2 - Smart wearable devices become more and more prevalent in the age of the Internet of Things. While people wear them as fitness trackers or full-fledged smartphones, they also come in unique versions as smartwatches for children. These watches allow parents to track the location of their children in real-time and offer a communication channel between parent and child. In this paper, we analyzed six smartwatches for children and the corresponding backend platforms and applications for security and privacy concerns. We structure our analysis in distinct attacker scenarios and collect and describe related literature outside academic publications. Using a cellular network Man-in-the-Middle setup, reverse engineering, and dynamic analysis, we found several severe security issues, allowing for sensitive data disclosure, complete watch takeover, and illegal remote monitoring functionality. KW - Security KW - Privacy Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-123548 SN - 978-1-4503-8833-7 SP - 1 EP - 10 ER - TY - JOUR A1 - Gierling, Markus A1 - Saatjohann, Christoph A1 - Dresen, Christian A1 - Köbe, Julia A1 - Rath, Benjamin A1 - Eckardt, Lars A1 - Schinzel, Sebastian T1 - Reviewing Cyber Security Research of Implantable Medical Rhythm Devices regarding Patients’ Risk JF - 86. Jahrestagung und Herztage 2020 der DGK N2 - Introduction: The recent publication of several critical cyber security issues in cardiac implantable devices and the resulting press coverage upsets affected users and their trust in medical device producers. Reviewing the published security vulnerabilities regarding networked medical devices, it raises the question, if the reporting media, the responsible security researchers, and the producers handle security vulnerabilities appropriately. Are the media reports of security vulnerabilities in medical devices meaningful in a way that patients can assess their respective risk for an attack via the security vulnerability? The collaboration between IT-security experts and clinicians aims at reviewing published security vulnerabilities of rhythm devices, and evaluate overall patients risks. Methodology: We performed a literature review on security vulnerabilities in implantable medical devices with a focus on cardiac devices. We analyzed (Fig. 1) the (1) requirements for an attacker and the (2) technical feasibility and clustered them in three different scenarios: The first scenario requires that the attacker physically approaches a victim with a programming device. The second scenario requires proximity to the victim, e.g., within a few meters. The third and strongest attacker scenario is a remote attack that doesn’t require any physical proximity to the victim. We then compare the attacker scenarios and (3) the overall patients’ risks with the press coverage (overhyped, adequate, underhyped). (4) The resulting overall patients’ risk was rated by clinicians (security vulnerability of patients’ data, dangerous programming possible). Results: Out of the three analyzed incidents, we found one to be underhyped, one to be overhyped, and one was appropriate compared to the medial coverage (Fig. 2). The most occurring technical issues were based on the absence of basic security primitives. The patient damage for all of the analyzed incidents was fatal in the worst-case scenario. Further, the patient damage and the overall patient risks are disjunct due to the missing capability of performing large scale attacks. Conclusion: The resulting overall patients’ risks may not adequately reflect the patient damage in the considered cases. Often, the overall patient risk is not as severe as the necessary attacker capabilities are high and it would require strongly motivated attackers to perform the attack. Therefore, most of the reviewed cases are considered with a smaller overall patient risk than implied by press reports. Reviewing the ongoing IT-Security trends regarding implantable medical devices shows an increasing focus on researching in the field of medical device security. Therefore, further findings in the near future are to be expected. To deal with this fact in a responsible way, proper proactive knowledge management is mandatory. We recommend medical staff to critically reflect reports in mass media due to possible sensationalism. Therefore, we propose a joint approach in combining the technical expertise of cyber security experts with clinical aspects of medical experts, to ensure a solid understanding of a newly published vulnerability. The combination of both communities promises to result in better predictions for patients’ risks from security vulnerabilities in implanted cardiac devices. KW - Cyber Security KW - Cardiac Implantable Devices Y1 - 2020 U6 - http://dx.doi.org/10.1007/s00392-020-01621-0 VL - Band 109, Supplement 1, April 2020 SP - 1 EP - 2 ER - TY - CHAP A1 - Gierling, Markus A1 - Dresen, Christian A1 - Eich, Hans A1 - Mittman, Karin A1 - Schinzel, Sebastian A1 - Haverkamp, Uwe T1 - Analysis and consequences of an imaging process concerning the cyber security of a networked computer tomography scanner T2 - STRAHLENTHERAPIE UND ONKOLOGIE KW - Cyber Security KW - networked computer tomography scanner Y1 - 2018 SP - 185 EP - 186 ER - TY - CHAP A1 - Müller, Jens A1 - Ising, Fabian A1 - Mla­de­nov, Vla­dis­lav A1 - Mainka, Chris­ti­an A1 - Schinzel, Sebastian A1 - Schwenk, Jörg T1 - Of­fice Do­cu­ment Se­cu­ri­ty and Pri­va­cy T2 - 14th USE­NIX Work­shop on Of­fen­si­ve Tech­no­lo­gies (WOOT 2020) N2 - OOXML and ODF are the de facto standard data formats for word processing, spreadsheets, and presentations. Both are XML-based, feature-rich container formats dating back to the early 2000s. In this work, we present a systematic analysis of the capabilities of malicious office documents. Instead of focusing on implementation bugs, we abuse legitimate features of the OOXML and ODF specifications. We categorize our attacks into five classes: (1) Denial-of-Service attacks affecting the host on which the document is processed. (2) Invasion of privacy attacks that track the usage of the document. (3) Information disclosure attacks exfiltrating personal data out of the victim's computer. (4) Data manipulation on the victim's system. (5) Code execution on the victim's machine. We evaluated the reference implementations – Microsoft Office and LibreOffice – and found both of them to be vulnerable to each tested class of attacks. Finally, we propose mitigation strategies to counter these attacks. KW - Cyber Security KW - Open Document Format KW - docx Y1 - 2020 UR - https://www.usenix.org/conference/woot20/presentation/muller PB - USENIX ER - TY - CHAP A1 - Willing, Markus A1 - Dresen, Christian A1 - Haverkamp, Uwe A1 - Schinzel, Sebastian T1 - Analyzing medical device connectivity and its effect on cyber security in german hospitals N2 - Background: Modern healthcare devices can be connected to computer networks and many western healthcareinstitutions run those devices in networks. At the same time, cyber attacks are on the rise and there is evidence thatcybercriminals do not spare critical infrastructure such as major hospitals, even if they endanger patients. Intuitively,the more and closer connected healthcare devices are to public networks, the higher the risk of getting attacked. Methods: To asses the current connectivity status of healthcare devices, we surveyed the field of German hospitalsand especially University Medical Center UMCs. Results: The results show a strong correlation between the networking degree and the number of medical devices.The average number of medical devices is 25.150, with a median of networked medical devices of 3.600. Actual keyusers of networked medical devices are the departments Radiology, Intensive Care, Radio-Oncology RO, NuclearMedicine NUC, and Anaesthesiology in the group of UMCs. In the next five years, the usage of networked medicaldevices will increase significantly in the departments of Surgery, Intensive Care, and Radiology. We detected a strongcorrelation between the degree of connectivity and the likelihood of being attacked.The survey answers regarding the cyber security status reveal a lack of security basics in some of the inquiredhospitals. We did discover successful attacks in hospitals with separated or subsidiary departments. A fusion ofcompetencies on an organizational level facilitates the right behavior here. Most hospitals rated themselvespredominantly positively in the self-assessment but also stated the usefulness of IT security insurance.Conclusions:Concluding our results, hospitals are already facing the consequences of omitted measures within theirgrowing pool of medical devices. Continuously relying on historically grown structures without adaption and trustingmanufactures to solve vectors is a critical behavior that could seriously endanger patients. Y1 - 2020 U6 - http://dx.doi.org/10.1186/s12911-020-01259-y PB - BMC Medical Informatics and Decision Making volume ER - TY - CHAP A1 - Puschner, Endres A1 - Saatjohann, Christoph A1 - Willing, Markus A1 - Dresen, Christian A1 - Köbe, Julia A1 - Rath, Benjamin A1 - Paar, Christof A1 - Eckardt, Lars A1 - Haverkamp, Uwe A1 - Schinzel, Sebastian T1 - Listen to Your Heart: Evaluation of the Cardiologic Ecosystem T2 - ARES 2021: The 16th International Conference on Availability, Reliability and Security N2 - Modern implantable cardiologic devices communicate via radio frequency techniques and nearby gateways to a backend server on the internet. Those implanted devices, gateways, and servers form an ecosystem of proprietary hardware and protocols that process sensitive medical data and is often vital for patients’ health. This paper analyzes the security of this Ecosystem, from technical gateway aspects, via the programmer, to configure the implanted device, up to the processing of personal medical data from large cardiological device producers. Based on a real-world attacker model, we evaluated different devices and found several severe vulnerabilities. Furthermore, we could purchase a fully functional programmer for implantable cardiological devices, allowing us to re-program such devices or even induce electric shocks on untampered implanted devices. Additionally, we sent several Art. 15 and Art. 20 GDPR inquiries to manufacturers of implantable cardiologic devices, revealing non-conforming processes and a lack of awareness about patients’ rights and companies’ obligations. This, and the fact that many vulnerabilities are still to be found after many vulnerability disclosures in recent years, present a worrying security state of the whole ecosystem. Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-139012 ER - TY - CHAP A1 - Ebbers, Simon A1 - Ising, Fabian A1 - Saatjohann, Christoph A1 - Schinzel, Sebastian T1 - Grand Theft App: Digital Forensics of Vehicle Assistant Apps T2 - ARES 2021: The 16th International Conference on Availability, Reliability and Security N2 - Due to the increasing connectivity of modern vehicles, collected data is no longer only stored in the vehicle itself but also transmitted to car manufacturers and vehicle assistant apps. This development opens up new possibilities for digital forensics in criminal investigations involving modern vehicles. This paper deals with the digital forensic analysis of vehicle assistant apps of eight car manufacturers. We reconstruct the driver’s activities based on the data stored on the smartphones and in the manufacturer’s backend. For this purpose, data of the Android and iOS apps of the car manufacturers Audi, BMW, Ford, Mercedes, Opel, Seat, Tesla, and Volkswagen were extracted from the smartphone and examined using digital forensic methods following forensics guidelines. Additionally, manufacturer data was retrieved using Subject Access Requests. Using the extensive data gathered, we reconstruct trips and refueling processes, determine parking positions and duration, and track the locking and unlocking of the vehicle. Our findings show that the digital forensic investigation of smartphone applications is a useful addition to vehicle forensics and should therefore be taken into account in the strategic preparation of future digital forensic investigations. Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-139031 ER -