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 - JOUR A1 - Schinzel, Sebastian A1 - Schmitt, Isabell T1 - Über Umwege - Seitenkanalangriffe auf Netzwerkanwendungen JF - iX - Magazin für professionelle Informationstechnik Y1 - 2012 IS - 11 ER - TY - CHAP A1 - Müller, Jens A1 - Brinkmann, Marcus A1 - Poddebniak, Damian A1 - Böck, Hanno A1 - Schinzel, Sebastian A1 - Smomrosvsky, Juraj A1 - Schwenk, Jörg T1 - “Johnny, you are fired!” – Spoofing OpenPGP and S/MIME Signatures in Emails T2 - 28th Usenix Security Symposium, Santa Clara, CA, USA N2 - OpenPGP and S/MIME are the two major standards to en-crypt and digitally sign emails. Digital signatures are sup-posed to guarantee authenticity and integrity of messages. Inthis work we show practical forgery attacks against variousimplementations of OpenPGP and S/MIME email signatureverification in five attack classes: (1) We analyze edge casesin S/MIME’s container format. (2) We exploit in-band sig-naling in the GnuPG API, the most widely used OpenPGPimplementation. (3) We apply MIME wrapping attacks thatabuse the email clients’ handling of partially signed mes-sages. (4) We analyze weaknesses in the binding of signedmessages to the sender identity. (5) We systematically testemail clients for UI redressing attacks.Our attacks allow the spoofing of digital signatures for ar-bitrary messages in 14 out of 20 tested OpenPGP-capableemail clients and 15 out of 22 email clients supportingS/MIME signatures. While the attacks do not target the un-derlying cryptographic primitives of digital signatures, theyraise concerns about the actual security of OpenPGP andS/MIME email applications. Finally, we propose mitigationstrategies to counter these attacks. Y1 - 2019 UR - https://www.usenix.org/conference/usenixsecurity19/presentation/muller EP - 18 ER - TY - CHAP A1 - Müller, Jens A1 - Brinkmann, Marcus A1 - Poddebniak, Damian A1 - Schinzel, Sebastian A1 - Schwenk, Jörg T1 - What's up John­ny? – Co­vert Con­tent At­tacks on Email End-to-End En­cryp­ti­on T2 - 17th In­ter­na­tio­nal Con­fe­rence on Ap­p­lied Cryp­to­gra­phy and Net­work Se­cu­ri­ty (ACNS 2019) N2 - We show practical attacks against OpenPGP and S/MIMEencryption and digital signatures in the context of email. Instead of tar-geting the underlying cryptographic primitives, our attacks abuse legiti-mate features of the MIME standard and HTML, as supported by emailclients, to deceive the user regarding the actual message content. Wedemonstrate how the attacker can unknowingly abuse the user as a de-cryption oracle by replying to an unsuspicious looking email. Using thistechnique, the plaintext of hundreds of encrypted emails can be leakedat once. Furthermore, we show how users could be tricked into signingarbitrary text by replying to emails containing CSS conditional rules.An evaluation shows that "out of" OpenPGP-capable email clients,as well as "out of" clients supporting S/MIME, are vulnerable to atleast one attack. We provide different countermeasures and discuss theiradvantages and disadvantages. Y1 - 2019 SP - 1 EP - 18 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 - 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 - Aviram, Nimrod A1 - Schinzel, Sebastian A1 - Somorovsky, Juraj A1 - Heninger, Nadia A1 - Dankel, Maik A1 - Steube, Jens A1 - Valenta, Luke A1 - Adrian, David A1 - Halderman, J. Alex A1 - Dukhovni, Viktor A1 - Käsper, Emilia A1 - Cohney, Shaanan A1 - Engels, Susanne A1 - Paar, Christof A1 - Shavitt, Yuval T1 - DROWN: Breaking TLS Using SSLv2 T2 - 25th Usenix Security Symposium Y1 - 2016 SP - 689 EP - 706 PB - Usenix Association. CY - Austin, TX. ER - TY - CHAP A1 - Freiling, Felix A1 - Schinzel, Sebastian T1 - Detecting Hidden Storage Side Channel Vulnerabilities in Networked Applications T2 - IFIP sec2011 - Future Challenges in Security and Privacy for Academia and Industry Y1 - 2011 SN - 978-3-642-21423-3 U6 - http://dx.doi.org/10.1007/978-3-642-21424-0_4 SP - 41 EP - 55 PB - Springer, Berlin, Heidelberg ET - Volume 354 ER - TY - CHAP A1 - Jager, Tibor A1 - Schinzel, Sebastian A1 - Somorovsky, Juraj T1 - Bleichenbacher's Attack Strinkes Again: Breaking PKCS#1 v1.5 in XML Encryption T2 - 17th European Symposium on Research in Computer Security (ESORCIS 2012) Y1 - 2012 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 -