Security Research in 2016: Measurements and Usability

Posted: February 27th, 2017 | Author: | Filed under: privacy, research, security | Tags: , , , , , , , , , , , , , , | No Comments »

My security research in 2016 focused on two broad categories: measurement-, and usability-studies. In this blog post, I briefly discuss the four most important papers we published in these domains in 2016.

Data-driven security and measurement studies

The Transport Layer Security (TLS) protocol is the building block of secure web communication. A number of important Internet applications rely on the TLS  protocol for the protection of exchanged information. One of these important applications is E-Mail, which despite of the growing use of mobile messengers, remains very popular. In a joint project with Wilfried, Aaron, and Martin we analyzed how TLS is used in the global E-Mail ecosystem. Our measurements consist of over 10 billion TLS handshakes against 20 Million global email services. Our findings showed that weak Diffie Hellman parameters are a serious threat for the security of the current E-Mail systems. We also showed that roughly one third of all analyzed E-Mail services supported the insecure plain-authentication method. Our paper got the award for best paper at ARES 2016, for the details on our research: read the paper and/or download our dataset.

number of email hosts that offer auth plain authentication (2016)

In 2016 we furthermore conducted a study on the effectiveness of state-of-the-art blocker tracking tools. Online tracking is a widespread practice for web services in order to tailor online advertisement as well as to identity the online behavior of people. Tracker-blocking tools such as Ghostery or AdBlock Plus are currently the only available solution for people to protect against tracking and malicious advertisement, yet little is known how effective these tools are. We performed the first large-scale measurement study on the effectiveness of tracker-blocking tools on websites as well as mobile apps. The research is part of our PriSAd research project (FH St. Pölten + nimbusec) and joint work with SBA Research (in particular Georg + Damjan), as well as Nick Nikiforakis from Stony Brook University. We will present our findings at the EuroS&P conference in Paris / April 2017. A preprint of our paper is available here.

Usability of Secure Mobile Applications

In addition to measurements on the usage of TLS in E-Mail services we tackled the correct usage of TLS in mobile applications. Android enables application developers to customize how TLS certificates are verified. Per default Android applications trust valid certificates based on its own CA store. Developers can however completely disable certificate validation (which is very bad and renders the security of TLS useless), or in best case pin certificates. Ultimately, users have to trust application developers to use TLS correctly. We outlined a method improve the correct usage of TLS in Android applications for end users, despite potential implementation bugs introduced by app developers. The main idea we proposed consists in intercepting calls to the Android TrustManager and pin TLS certificates on the fly. Damjan presented our method and proof-of-concept implementation at the IFIP Networking conference.

Finally, in 2016 we conducted a usability study on the state-of-the-art secure messenger: Signal. The Signal protocol provides both forward as well as future secrecy. Signal also works if message recipients are offline. In 2016 WhatsApp rolled out encrypted communication based on Signal and the cryptographic protocol is now used by more than a billion users worldwide. Signal makes the use of state-of-the-art cryptography easy, the whole protocol is however broken if an attacker manages to compromise the key-exchange servers of e.g. Signal or WhatsApp. We studied how users perform on countering targeted attacks with Signal’s fingerprint verification feature. We found that 75% of our study participants failed to correctly verify the identity of other Signal users. Read the paper for further details on our study and our suggested usability improvements for the Signal messenger.

example warning dialog from Signal once identity key changes

What else happened in 2015

Posted: November 25th, 2015 | Author: | Filed under: privacy, random, security | No Comments »

Time to post a short update on things that happened, since I attended WWW in Florence 2015. In 2015, I devoted the majority of my research time on the development of the Usable Privacy Box (upribox). The upribox is a RaspberryPi-based WiFi router that automatically filters advertisement and optionally routes traffic through the Tor anonymity network. I presented the upribox at the CCC Camp in Berlin and ITSecX 2015.

nysos v3 – home theater PC

Posted: July 5th, 2015 | Author: | Filed under: personal, random | Tags: , , , , , | No Comments »

In June 2015, i replaced my old home theater PC with new hardware. This is the third time I upgraded my HTPC hardware, thus the name: nysos v3. I am now using an AMD Kabini APU, which resulted in quite some performance improvements for the full-encryption RAID5 storage of my setup. In May, I attended the WWW15 in Florence, and could also see the original painting that inspired my current online handly (dio)nysos .

Caravaggio at Uffizi Florence


Bye Bye Facebook

Posted: December 15th, 2014 | Author: | Filed under: personal, privacy | Tags: , , , , , , , | 1 Comment »

I will close my Facebook account for good on the 31st of December 2014. It is no secret that Facebook is bad for your personal information and ultimately leads to security problems (shameless promo of my own research e.g. 1,2,3). Originally I intended to close my account once I am done with my PhD. One year later it is finally time to say bye bye Facebook.

Some advice on saving your Facebook data before you close your account:

See you guys offline!

*SNOOB might stop working soon, once Facebook rolls out the Graph 2.0 API.

UPC IPv6 Umstellung

Posted: December 11th, 2014 | Author: | Filed under: personal | Tags: , , , , , , | 2 Comments »

Vor rund drei Wochen bin ich von UPC Österreich mit einer Umstellung auf IPv6 “beglückt” worden. Wobei die Umstellung auf den Dual-Stack Lite vorab ankündigt worden ist, kam die eigentliche Umstellung für mich doch etwas überraschend. Ich hatte den Reboot des Modems bemerkt und hatte mich zuerst über mögliche Security/Performance Fixes für mein Modem gefreut.

Innerhalb weniger Stunden musste ich jedoch feststellen dass das Portforwarding auf meine interne Linuxbox nicht mehr funktionierte. UPC verwendet Dual-Stack Lite, somit wird UPC Kunden keine routbare IPv4 Adresse mehr zugewiesen. Wenn man sich an den Support von UPC wendet, kann bitten wieder auf IPv4 umgestellt zu werden. Ich wollte mich der Zukunft allerdings nicht ganz verwehren.

Mit der IPv6 Umstellung von UPC bekommt jedes interne IPv6-fähige Gerät im internen Netzwerk automatisch eine globale IPv6 Adresse zugewiesen. Ich habe daher die IPv6 Adresse meiner Linuxbox statisch konfiguriert und sämtliche DNS Einträge von A- auf AAAA-Records geändert. Somit ist mein Linuxrechner wieder über das Internet erreichbar. Allerdings kann ich mich nur mehr über IPv6 Netzwerke auf meine Box verbinden, glücklicherweise hat die FH St. Pölten bereits seit Längerem einen IPv6 Tunnelbroker eingerichtet. Webseiten die ich auf meiner Linuxbox hoste (wie zum Beispiel dieses Blog), sind dank CloudFlare auch über IPv4-Netze problemlos erreichbar. Ein kleineres Problem musste  ich dennoch fixen: Ich verwende den UPC SMTP als Mail Relay um mir Benachrichtigungen über den Zustand meiner Box zu schicken. Da der SMTP Relay momentan keine Emails von ihrem eigenen IPv6 Adressbereich akzeptieren (!), musste ich meine postfix Konfiguration anpassen um Emails nur über IPv4 zu versenden.

Update 5.5.2015:

Da sich das UPC Dualstack Netz als nicht sehr stabil erwiesen hat, hatte ich beim UPC Support angerufen um wieder auf IPv4-only umgestellt zu werden. Die Umstellung verlief soweit problemlos und die Zukunft kann somit noch ein bisschen warten.